Alpheratz belongs to Andromeda, but is part of the Great Square

The star Alpheratz is the brightest star in the famous star pattern known as the Great Square of Pegasus. Alpheratz connects Pegasus to the constellation Andromeda. And people often find the Andromeda Galaxy by star-hopping from Alpheratz – to Mirach and Mu Andromedae – to the galaxy. Chart via EarthSky.

The Great Square of Pegasus

There’s a large, easily recognizable pattern of four medium-bright stars – up in the sky on October and November evenings – that stargazers call the Great Square of Pegasus. However, one of these stars doesn’t formally belong to the constellation Pegasus. It’s Alpheratz, the brightest star in the constellation Andromeda. In fact, many people use this star to locate the Andromeda Galaxy in the night sky. While it appears as a single star to the unaided eye, Alpheratz is actually a tight double star system.

When can you see the star Alpheratz?

This star reaches its midnight culmination – its highest point in the sky at midnight – on October 9. So, it’s generally considered an autumn star for Northern Hemisphere observers. Yet you can see it in the summertime when it rises late at night. And by late winter, Alpheratz is setting with the sun.

At magnitude 2.06, Alpheratz isn’t as bright as the sky’s brightest stars. But you can spot it easily, except in very light-polluted areas.

Use Alpheratz to find the Andromeda Galaxy

The Andromeda galaxy, also known as M31, is the nearest large spiral galaxy to Earth. It’s the most distant thing we can see with the unaided eye, though you’ll need a dark sky to see it. Autumn is a good time to look.

People often find the Andromeda Galaxy by star-hopping from Alpheratz to two other stars in the constellation Andromeda, Mirach and Mu Andromedae. After you find those two stars, you can draw a line between them, and extend that line to find the galaxy, as shown in the chart below.

A star map of the constellation Andromeda showing the locations of the Andromeda Galaxy (M31) and the Triangulum Galaxy (M33). Image via IAU/ Sky & Telescope/ Wikimedia Commons/ Attribution 3.0 Unported (CC BY 3.0).

Science of Alpheratz

Alpheratz, at a relatively nearby distance of 97 light-years, is actually two stars orbiting about a common center of gravity every 97 days. We know it’s a binary stellar system because Alpheratz’s light spectrum shows two distinct sets of spectroscopic lines.

The larger of the pair is almost four times the sun’s mass, close to three times its size, and 200 times the sun’s total brightness. Its surface temperature is high, almost 14,000 Kelvin (approximately 27,400 Fahrenheit or 13,700 Celsius), more than twice that of our sun (that has a surface temperature of less than half that at 5,778 Kelvin). The spectral class of this star is B8p. The B8 represents a star that is much hotter and more massive than our sun. The “p” indicates that this is a “peculiar” star. It is peculiar in the sense that its spectrum reveals an unexpected amount of manganese and mercury.

The smaller companion is almost twice the sun’s mass and over 1 1/2 times its size. Its surface temperature is also hotter than the sun’s, at 8,500 Kelvin (14,840 F or 8,227 C), with a total brightness 10 times that of the sun.

Together, these two hot stars appear blue in the sky.

History and mythology

The most interesting part of this star’s history, from our modern perspective, is its assignment to the constellation Andromeda in the 1930s by the International Astronomical Union (IAU). Before that, Alpheratz was often referred to as Delta Pegasi, indicating that it was the fourth-brightest star in Pegasus. But some classical star charts showed it as part of Andromeda. So, it was considered part of the constellation Pegasus, or part of the constellation Andromeda, or, by some people, part of both constellations. Today, Alpheratz is officially Alpha Andromedae, the brightest star in Andromeda.

Early Arabian stargazers certainly saw Alpheratz as part of Pegasus, not Andromeda. We know this because the name Alpheratz derives from an Arabic phrase meaning the horse’s navel. This is an obvious reference to Pegasus the Flying Horse. Also, according to Richard Hinckley Allen, in his classic book “Star Names, Their Lore and Meaning,” Alpheratz was also called Sirrah, a derivation of another Arabic name, Surrat al Faras or the horse’s navel.

View at EarthSky Community Photos. | Jan Curtis in Cheyenne, Wyoming, used a telephoto lens to capture this view of Messier 31, the Andromeda galaxy, on September 25, 2024. Jan wrote: “With the Fujifilm X-T5, the sensor resolution is 45 MB. As a result, deep-sky images can be chopped without loss of resolution. M31 is well placed this time of year for all night viewing. Taken from Cheyenne, WY, under clear Bortle 5.5 skies.” Thank you, Jan!

Bottom line: Alpheratz appears to our eyes as a single star but it is actually a close binary star system. Many stargazers use it to locate the Andromeda Galaxy.

Read more Andromeda and Milky Way galaxies already merging?

The post Alpheratz belongs to Andromeda, but is part of the Great Square first appeared on EarthSky.

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The star Alpheratz is the brightest star in the famous star pattern known as the Great Square of Pegasus. Alpheratz connects Pegasus to the constellation Andromeda. And people often find the Andromeda Galaxy by star-hopping from Alpheratz – to Mirach and Mu Andromedae – to the galaxy. Chart via EarthSky.

The Great Square of Pegasus

There’s a large, easily recognizable pattern of four medium-bright stars – up in the sky on October and November evenings – that stargazers call the Great Square of Pegasus. However, one of these stars doesn’t formally belong to the constellation Pegasus. It’s Alpheratz, the brightest star in the constellation Andromeda. In fact, many people use this star to locate the Andromeda Galaxy in the night sky. While it appears as a single star to the unaided eye, Alpheratz is actually a tight double star system.

When can you see the star Alpheratz?

This star reaches its midnight culmination – its highest point in the sky at midnight – on October 9. So, it’s generally considered an autumn star for Northern Hemisphere observers. Yet you can see it in the summertime when it rises late at night. And by late winter, Alpheratz is setting with the sun.

At magnitude 2.06, Alpheratz isn’t as bright as the sky’s brightest stars. But you can spot it easily, except in very light-polluted areas.

Use Alpheratz to find the Andromeda Galaxy

The Andromeda galaxy, also known as M31, is the nearest large spiral galaxy to Earth. It’s the most distant thing we can see with the unaided eye, though you’ll need a dark sky to see it. Autumn is a good time to look.

People often find the Andromeda Galaxy by star-hopping from Alpheratz to two other stars in the constellation Andromeda, Mirach and Mu Andromedae. After you find those two stars, you can draw a line between them, and extend that line to find the galaxy, as shown in the chart below.

A star map of the constellation Andromeda showing the locations of the Andromeda Galaxy (M31) and the Triangulum Galaxy (M33). Image via IAU/ Sky & Telescope/ Wikimedia Commons/ Attribution 3.0 Unported (CC BY 3.0).

Science of Alpheratz

Alpheratz, at a relatively nearby distance of 97 light-years, is actually two stars orbiting about a common center of gravity every 97 days. We know it’s a binary stellar system because Alpheratz’s light spectrum shows two distinct sets of spectroscopic lines.

The larger of the pair is almost four times the sun’s mass, close to three times its size, and 200 times the sun’s total brightness. Its surface temperature is high, almost 14,000 Kelvin (approximately 27,400 Fahrenheit or 13,700 Celsius), more than twice that of our sun (that has a surface temperature of less than half that at 5,778 Kelvin). The spectral class of this star is B8p. The B8 represents a star that is much hotter and more massive than our sun. The “p” indicates that this is a “peculiar” star. It is peculiar in the sense that its spectrum reveals an unexpected amount of manganese and mercury.

The smaller companion is almost twice the sun’s mass and over 1 1/2 times its size. Its surface temperature is also hotter than the sun’s, at 8,500 Kelvin (14,840 F or 8,227 C), with a total brightness 10 times that of the sun.

Together, these two hot stars appear blue in the sky.

History and mythology

The most interesting part of this star’s history, from our modern perspective, is its assignment to the constellation Andromeda in the 1930s by the International Astronomical Union (IAU). Before that, Alpheratz was often referred to as Delta Pegasi, indicating that it was the fourth-brightest star in Pegasus. But some classical star charts showed it as part of Andromeda. So, it was considered part of the constellation Pegasus, or part of the constellation Andromeda, or, by some people, part of both constellations. Today, Alpheratz is officially Alpha Andromedae, the brightest star in Andromeda.

Early Arabian stargazers certainly saw Alpheratz as part of Pegasus, not Andromeda. We know this because the name Alpheratz derives from an Arabic phrase meaning the horse’s navel. This is an obvious reference to Pegasus the Flying Horse. Also, according to Richard Hinckley Allen, in his classic book “Star Names, Their Lore and Meaning,” Alpheratz was also called Sirrah, a derivation of another Arabic name, Surrat al Faras or the horse’s navel.

View at EarthSky Community Photos. | Jan Curtis in Cheyenne, Wyoming, used a telephoto lens to capture this view of Messier 31, the Andromeda galaxy, on September 25, 2024. Jan wrote: “With the Fujifilm X-T5, the sensor resolution is 45 MB. As a result, deep-sky images can be chopped without loss of resolution. M31 is well placed this time of year for all night viewing. Taken from Cheyenne, WY, under clear Bortle 5.5 skies.” Thank you, Jan!

Bottom line: Alpheratz appears to our eyes as a single star but it is actually a close binary star system. Many stargazers use it to locate the Andromeda Galaxy.

Read more Andromeda and Milky Way galaxies already merging?

The post Alpheratz belongs to Andromeda, but is part of the Great Square first appeared on EarthSky.

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Is this white dwarf exoplanet a preview of Earth’s fate?

This video depicts a possible fate for Earth when the sun expands into a red giant star. If the red giant sheds its mass quickly enough to allow Earth to migrate to a wider orbit, our planet will escape being engulfed by the expanding surface of the red giant. A newly-discovered white dwarf exoplanet seems to have done exactly that. Video via Adam Makarenko/ UC Berkeley/ YouTube (Creative Commons Attribution License, reuse allowed).

Our fall fund-raiser is going on now. Please help EarthSky keep going. Donate to EarthSky today!

• White dwarf stars are the remaining small, hot cores of dead stars. They form after a star expands into a red giant, then contracts back into a white dwarf.
• Planets orbiting close to their stars would be consumed in the red giant phase. But could Earth escape when the sun becomes a red giant billions of years from now?
• Astronomers discovered an Earth-sized exoplanet orbiting a white dwarf 4,000 light-years away. Its survival could mean that Earth might escape its fiery fate as well.

Earth-sized exoplanet orbiting a white dwarf star

Scientists say that about 5 billion years from now, the sun will become a red giant star. It will consume Mercury, Venus … and probably Earth. And then it will shrink to a tiny white dwarf star as it dies. But the discovery of an Earth-sized planet orbiting a white dwarf 4,000 light-years away shows that Earth might actually be able to survive this fiery fate.

A team of astronomers, led by the University of California (UC) Berkeley, found the planet using the W. M. Keck Observatory on Maunakea, Hawaii Island. Lead author Keming Zhang and his colleagues published their peer-reviewed findings in Nature Astronomy on September 26, 2024. You can also read the free preprint on arXiv. Zhang was formerly at UC Berkeley in California, and now is at UC San Diego.

White dwarf exoplanet: Earth’s future?

The rocky planet is about the size of Earth, and orbits a white dwarf star 4,000 light-years away, close to the central bulge of our galaxy. A white dwarf is the remaining burned-out core of a dead star. So this star will have swelled into a red giant first before entering this white dwarf phase.

In most scenarios, the Earth-sized planet should have been consumed and destroyed by the red giant. But it’s still there. Does that mean Earth could also escape a cataclysmic fate?

Could Earth move out to safety?

According to the researchers, there’s a chance. As our sun expands, it will also shed its mass. That means its gravitational attraction would lessen. The researchers noted that, if our sun sheds this mass quickly enough, it could have the effect of releasing Earth into a more distant orbit. And this could be the difference between being engulfed by the growing sun and remaining scorched but intact.

The researchers calculated that, in this scenario, Earth’s new orbit may be about twice the size it is now. And, interestingly, the newly-discovered planet is in an orbit about twice the size of Earth’s.

It may be a slim chance of survival, but it is possible. Earth would still no longer habitable for life itself as we know it now, but the planet itself would still exist. Lu added:

Whether life can survive on Earth through that (red giant) period is unknown. But certainly the most important thing is that Earth isn’t swallowed by the Sun when it becomes a red giant. This system that Keming found is an example of a planet – probably an Earth-like planet originally on a similar orbit to Earth – that survived its host star’s red giant phase.

Microlensing discovery

Astronomers first detected this planetary system back in 2020. They found it using the microlensing technique. That was when the white dwarf passed in front of a more distant star. The white dwarf magnified the background star’s light by 1,000 times. How does that happen? In microlensing, the gravity of the closer star acts like a lens, which focuses and amplifies the light from the more distant star.

The researchers called this particular microlensing event KMT-2020-BLG-0414. They used the Korea Microlensing Telescope Network (KMTNet) in the Southern Hemisphere to detect it, hence “KMT.”

The astronomers re-examined the system in 2023. This time, they used Keck Observatory’s second-generation Near-Infrared Camera (NIRC2), along with the adaptive optics system. This allowed them to eliminate the blur caused by Earth’s atmosphere.

Regular star or white dwarf?

If the star was a regular star, then it should have been seen in the Keck images. But the astronomers saw nothing. This led them to conclude that the star was actually a white dwarf. Zhang said:

Our conclusions are based on ruling out the alternative scenarios, since a normal star would have been easily seen. Because the lens is both dark and low mass, we concluded that it can only be a white dwarf.

Co-author Jessica Lu at UC Berkeley added:

This is a case of where seeing nothing is actually more interesting than seeing something,” said Lu, who looks for microlensing events caused by free-floating stellar-mass black holes in the Milky Way.

UC Berkeley astronomer Joshua Bloom also said:

Microlensing has turned into a very interesting way of studying other star systems that can’t be observed and detected by the conventional means, i.e. the transit method or the radial velocity method. There is a whole set of worlds that are now opening up to us through the microlensing channel, and what’s exciting is that we’re on the precipice of finding exotic configurations like this.

View larger. | Artist’s concept of an Earth-like planet orbiting a white dwarf star. Could Earth also survive our sun’s future red giant phase? Image via Adam Makarenko/ W. M. Keck Observatory.

Bottom line: Astronomers have discovered an Earth-sized planet orbiting a white dwarf star. Does this white dwarf exoplanet mean Earth could survive the death of the sun?

Source: An Earth-mass planet and a brown dwarf in orbit around a white dwarf

Source (preprint): An Earth-Mass Planet and a Brown Dwarf in Orbit Around a White Dwarf

Via W. M. Keck Observatory

Read more: Giant planets orbiting white dwarfs: 1st images?

Read more: Solar system’s future seen: 1st planet around a white dwarf

The post Is this white dwarf exoplanet a preview of Earth’s fate? first appeared on EarthSky.

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This video depicts a possible fate for Earth when the sun expands into a red giant star. If the red giant sheds its mass quickly enough to allow Earth to migrate to a wider orbit, our planet will escape being engulfed by the expanding surface of the red giant. A newly-discovered white dwarf exoplanet seems to have done exactly that. Video via Adam Makarenko/ UC Berkeley/ YouTube (Creative Commons Attribution License, reuse allowed).

Our fall fund-raiser is going on now. Please help EarthSky keep going. Donate to EarthSky today!

• White dwarf stars are the remaining small, hot cores of dead stars. They form after a star expands into a red giant, then contracts back into a white dwarf.
• Planets orbiting close to their stars would be consumed in the red giant phase. But could Earth escape when the sun becomes a red giant billions of years from now?
• Astronomers discovered an Earth-sized exoplanet orbiting a white dwarf 4,000 light-years away. Its survival could mean that Earth might escape its fiery fate as well.

Earth-sized exoplanet orbiting a white dwarf star

Scientists say that about 5 billion years from now, the sun will become a red giant star. It will consume Mercury, Venus … and probably Earth. And then it will shrink to a tiny white dwarf star as it dies. But the discovery of an Earth-sized planet orbiting a white dwarf 4,000 light-years away shows that Earth might actually be able to survive this fiery fate.

A team of astronomers, led by the University of California (UC) Berkeley, found the planet using the W. M. Keck Observatory on Maunakea, Hawaii Island. Lead author Keming Zhang and his colleagues published their peer-reviewed findings in Nature Astronomy on September 26, 2024. You can also read the free preprint on arXiv. Zhang was formerly at UC Berkeley in California, and now is at UC San Diego.

White dwarf exoplanet: Earth’s future?

The rocky planet is about the size of Earth, and orbits a white dwarf star 4,000 light-years away, close to the central bulge of our galaxy. A white dwarf is the remaining burned-out core of a dead star. So this star will have swelled into a red giant first before entering this white dwarf phase.

In most scenarios, the Earth-sized planet should have been consumed and destroyed by the red giant. But it’s still there. Does that mean Earth could also escape a cataclysmic fate?

Could Earth move out to safety?

According to the researchers, there’s a chance. As our sun expands, it will also shed its mass. That means its gravitational attraction would lessen. The researchers noted that, if our sun sheds this mass quickly enough, it could have the effect of releasing Earth into a more distant orbit. And this could be the difference between being engulfed by the growing sun and remaining scorched but intact.

The researchers calculated that, in this scenario, Earth’s new orbit may be about twice the size it is now. And, interestingly, the newly-discovered planet is in an orbit about twice the size of Earth’s.

It may be a slim chance of survival, but it is possible. Earth would still no longer habitable for life itself as we know it now, but the planet itself would still exist. Lu added:

Whether life can survive on Earth through that (red giant) period is unknown. But certainly the most important thing is that Earth isn’t swallowed by the Sun when it becomes a red giant. This system that Keming found is an example of a planet – probably an Earth-like planet originally on a similar orbit to Earth – that survived its host star’s red giant phase.

Microlensing discovery

Astronomers first detected this planetary system back in 2020. They found it using the microlensing technique. That was when the white dwarf passed in front of a more distant star. The white dwarf magnified the background star’s light by 1,000 times. How does that happen? In microlensing, the gravity of the closer star acts like a lens, which focuses and amplifies the light from the more distant star.

The researchers called this particular microlensing event KMT-2020-BLG-0414. They used the Korea Microlensing Telescope Network (KMTNet) in the Southern Hemisphere to detect it, hence “KMT.”

The astronomers re-examined the system in 2023. This time, they used Keck Observatory’s second-generation Near-Infrared Camera (NIRC2), along with the adaptive optics system. This allowed them to eliminate the blur caused by Earth’s atmosphere.

Regular star or white dwarf?

If the star was a regular star, then it should have been seen in the Keck images. But the astronomers saw nothing. This led them to conclude that the star was actually a white dwarf. Zhang said:

Our conclusions are based on ruling out the alternative scenarios, since a normal star would have been easily seen. Because the lens is both dark and low mass, we concluded that it can only be a white dwarf.

Co-author Jessica Lu at UC Berkeley added:

This is a case of where seeing nothing is actually more interesting than seeing something,” said Lu, who looks for microlensing events caused by free-floating stellar-mass black holes in the Milky Way.

UC Berkeley astronomer Joshua Bloom also said:

Microlensing has turned into a very interesting way of studying other star systems that can’t be observed and detected by the conventional means, i.e. the transit method or the radial velocity method. There is a whole set of worlds that are now opening up to us through the microlensing channel, and what’s exciting is that we’re on the precipice of finding exotic configurations like this.

View larger. | Artist’s concept of an Earth-like planet orbiting a white dwarf star. Could Earth also survive our sun’s future red giant phase? Image via Adam Makarenko/ W. M. Keck Observatory.

Bottom line: Astronomers have discovered an Earth-sized planet orbiting a white dwarf star. Does this white dwarf exoplanet mean Earth could survive the death of the sun?

Source: An Earth-mass planet and a brown dwarf in orbit around a white dwarf

Source (preprint): An Earth-Mass Planet and a Brown Dwarf in Orbit Around a White Dwarf

Via W. M. Keck Observatory

Read more: Giant planets orbiting white dwarfs: 1st images?

Read more: Solar system’s future seen: 1st planet around a white dwarf

The post Is this white dwarf exoplanet a preview of Earth’s fate? first appeared on EarthSky.

from EarthSky https://ift.tt/9iejIN1

Double stars: How to find, observe and enjoy them

View larger. | The Big Dipper has 2 parts: a bowl and a handle. Look closely at the handle stars hanging down from the Big Dipper in this photo. It contains one of the most famous double stars. Can you spot it? Image via Unsplash/ Nadiia Ploshchenko.

Double stars are two stars that appear close together in the sky. They might be physically related or they might only appear double because they lie together along our line of sight. Double stars that aren’t gravitationally bound systems – but are only located near one another along our line of sight – are optical doubles. Double stars that are gravitationally bound and orbit a common center of mass are true binary star systems. Scientists believe that most stars in our Milky Way galaxy – unlike our sun – orbit the galactic center in binary pairs. In fact, some estimates suggest that up to 85% of stars might reside in binary systems.

Like snowflakes, no two double-star systems are alike. So gazing at them is a lot of fun. You’ll see a huge range of star brightnesses, and a range of different distances between the stars. And sometimes you’ll notice a contrast in colors between the two stars. This post will give you some tips on observing double stars with your eye alone, with binoculars and, if you want to take the plunge, with a small telescope. Read on, and learn to enjoy the sky’s delightful double stars!

Double star observing tips

To see double stars, Earth’s atmosphere needs to be still. A lot of motion in different layers of our atmosphere makes a star waver and dance. Astronomers will then say the seeing is poor. On nights of bad seeing, it can be very difficult for an observer with a telescope to “split” a binary pair into its two components. You might only see a single star. Whenever you’re looking toward a horizon, you’re looking through a thicker layer of atmosphere. So it’s better – when observing double stars – if your target is located near the sky’s zenith (overhead).

A couple of other observing factors contribute to whether you can see both components of a double star. Are you under a dark sky? How bright are the two stars you’re trying to see, that is, what are their magnitudes? Stars that shine at 5th or 6th magnitude are quite challenging but possible to observe. And lastly, how far apart are the stars? For anything closer together than 5 arcminutes you’ll probably want to try using binoculars.

Mizar and Alcor in the Big Dipper

For those new to double stars and new to observing the sky, it’s best to start with something simple. The optical double star Mizar and Alcor in the Big Dipper are a cinch to find. The Big Dipper asterism is a pattern that stands out due to its large size and bright stars. It’s visible year-round from Northern Hemisphere latitudes like those in the northern U.S. and Canada.

View at EarthSky Community Photos. | Susan Jensen captured this image on September 6, 2024, and wrote: “Right place, right time! Standing on a gravel road in the middle of nowhere, looking across a stubble field. This slow-moving, vibrant meteor stopped me in my tracks! I was shooting the Big Dipper with the shutter locked to catch multiple frames for stacking when this monster did a slow flyby. How lucky that I was able to capture it!” Thank you, Susan! Notice how you can see the 2 stars, Mizar and Alcor, snug together at the bend in the handle of the Big Dipper?

Seven stars make up the Big Dipper: four in the bowl and three in the handle. The middle of the three handle stars is the Mizar/Alcor pair. The stars appear about 12 arcminutes apart. So anyone with fair eyesight should be able to see them as two stars. Mizar is the brighter of the two, and Alcor is the dimmer one. Mizar shines at magnitude 2.2 from some 82 light-years away. And Alcor shines at magnitude 4 from about 81 light-years distant. These two stars are physically bound in space.

This chart of the Big Dipper includes a label for Mizar, while its companion star, Alcor, appears next to it without a label.

Mizar and Alcor with magnification

If you’re unable to split Mizar and Alcor with your eyes alone, go ahead and turn a pair of binoculars on them. Splitting Mizar and Alcor was a test of eyesight once upon a time. If you can’t see both without optical aid, maybe it’s time for a visit to the eye doctor?

To go deeper with these stars, look through a telescope and you’ll find that Mizar itself is a double star. The two parts of Mizar are 14 arcseconds apart. Fun fact: each of the two parts of Mizar are also double stars, making it a quadruple star system, not counting Alcor. Alcor is a double star, so in total, this is a sextuple star system.

Through a telescope, you can turn the double star Mizar and Alcor into a triple system. At left is Alcor, and at right is Mizar and its companion. Image via Nikolay Nikolov/ Wikimedia Commons (CC BY-SA 4.0).

View at EarthSky Community Photos. | Abdul Thomas captured this image through an 8″ telescope in Leeds, UK, on February 2, 2024. Abdul wrote: “Mizar and Alcor, a double star system in the northern constellation of Ursa Major the Great Bear. These two stars are clearly visible with the unaided eye and located on the handle of The Plough (Big Dipper) asterism.” Thank you, Abdul!

Scorpius holds 2 double star targets

Scorpius, a constellation best viewed in the Northern Hemisphere summer, has two pairs of double stars that you can try to separate using just your eyes. The easier target is Mu Scorpii. Its two components are a binary pair, one at magnitude 2.9 and one at 3.5. Use the chart here to find Mu and then let your eyes adjust to the dark to see if you can spot both the Mu stars. This pair is a little under 6 arcminutes apart.

If you can see them both without optical aid, try looking just below them for the two Zeta stars. These stars are merely an optical double. Zeta 1 is nearly 40 times farther away than Zeta 2. Zeta 2 is magnitude 3.6, just a hair dimmer than the dimmer member of Mu you spotted above. Zeta 1 is the hardest to spot at magnitude 4.7. If you need to use binoculars, go ahead and get a look, then try again without them. These two are about 6 1/2 arcminutes apart.

Mu Scorpii should not be a difficult pair to “split” with the unaided eye. But the Zeta Scorpii pair will be more challenging. Use the bright red star Antares as a guide to find Mu and Zeta.

Alpha Capricorni with or without binoculars

Like the double stars in Scorpius, the Alpha star in Capricornus will be visible to some people without any optical aid, while others will need to use a pair of binoculars. Alpha Capricorni is an optical double, that is, they only appear close together from our point of view. Alpha 1 shines at magnitude 4.2 and lies 633 light-years away. Its partner, Alpha 2, which also bears the name Algedi, shines at magnitude 3.5 and lies 107 light-years away. The pair are about 6 1/2 arcminutes apart.

Alpha Capricorni is a double star that some may see without optical aid while others will need to use binoculars.

Theta Tauri in the Bull’s head

Next up is Theta Tauri. You might be able to spy both parts of this double star without optical aid, but a steadily held pair of binoculars will make it easier. Theta Tauri is in the V-shape of Taurus’ head, near the brilliant, reddish Aldebaran. Theta 1 and Theta 2 lie about 5 1/2 arcminutes apart and shine at magnitudes 3.3 and 3.8.

When the two parts of the double star are similar in brightness or magnitude, they’re easier to split than when one is brighter than the other. Is Theta Tauri easier for you to see than Mu Scorpii?

Theta Tauri, the yellow and blue pair at center, lie close to brilliant Aldebaran in Taurus’ star cluster the Hyades. Image via NASA/ ESA/ STScI/ Wikimedia Commons (CC BY-SA 4.0).

Epsilon Lyrae, the famous Double Double

The Double Double – Epsilon Lyrae – is a system of two pairs of double stars in the summer constellation Lyra the Harp. But you can still see Lyra in the evening through November before it sets in the west. Lyra has many double stars. How many can you find if you sweep the area in binoculars?

The famous Double Double has stars around magnitude 5. The stars are simple to find, next to brilliant Vega. Epsilon 1 and Epsilon 2 are about 3 arcminutes apart, with the additional two parts of both Epsilon 1 and Epsilon 2 each being about 2 arcseconds apart. Look for the first pair of stars in binoculars. You may need a telescope to see each of those stars separate into two more stars.

The constellation Lyra the Harp. It’s made of a triangle and a parallelogram. Its brightest star is Vega. Look next to it for the famous Epsilon Lyrae, a double-double star, really 4 stars in all.

Epsilon Lyrae is the famous Double Double. Under magnification, you should be able to see the double stars split into double stars themselves. Image via Nikolay Nikolov/ Wikimedia Commons (CC BY-SA 4.0).

Colorful Albireo

Albireo – or Beta Cygni – has earned the nickname of the most beautiful double star in the heavens. This blue and yellow pair lies just 35 arcseconds apart from our point of view. Astronomers don’t yet know if this is a physically bound pair or just a line-of-sight coincidence. The two parts of Albireo shine at magnitudes 3.1 and 5.1. Albireo marks the head of Cygnus the Swan.

Albireo is a tighter pair discernible using larger binoculars or a small telescope. The star lies in the constellation Cygnus the Swan, opposite the bright star Deneb.

View at EarthSky Community Photos. | David Hoskin of Canada captured this on June 6, 2024, and wrote: “Albireo (Beta Cygni) is a colorful double star in the constellation Cygnus.” Thank you, David!

The Southern Hemisphere’s Alpha Centauri

The brightest star in Centaurus, found in the Southern Hemisphere, is not only a multiple star system but the closest star to Earth at 4.37 light-years. Alpha Centauri can be split into its components A and B. They are a true binary pair, being gravitationally bound.

Alpha Centauri – which is visible to the unaided eye as a single bright star – is a tighter pair that you can split using a small telescope. Use the bright constellation Crux, the Southern Cross, as a guide to find Alpha Centauri.

Using a 110mm refractor (a 4.3-inch telescope), the photographer captured this image of the double star Alpha Centauri in daylight. Image via Skatebiker/ Wikimedia Commons (CC BY-SA 4.0).

Once you get used to spotting double stars, you’ll find them in constellations everywhere. Good luck, and clear skies!

Bottom line: This double star observing guide gives you a range of choices for observing with your eyes alone. Or go further using binoculars or a telescope.

The post Double stars: How to find, observe and enjoy them first appeared on EarthSky.

from EarthSky https://ift.tt/fgJURbX

View larger. | The Big Dipper has 2 parts: a bowl and a handle. Look closely at the handle stars hanging down from the Big Dipper in this photo. It contains one of the most famous double stars. Can you spot it? Image via Unsplash/ Nadiia Ploshchenko.

Double stars are two stars that appear close together in the sky. They might be physically related or they might only appear double because they lie together along our line of sight. Double stars that aren’t gravitationally bound systems – but are only located near one another along our line of sight – are optical doubles. Double stars that are gravitationally bound and orbit a common center of mass are true binary star systems. Scientists believe that most stars in our Milky Way galaxy – unlike our sun – orbit the galactic center in binary pairs. In fact, some estimates suggest that up to 85% of stars might reside in binary systems.

Like snowflakes, no two double-star systems are alike. So gazing at them is a lot of fun. You’ll see a huge range of star brightnesses, and a range of different distances between the stars. And sometimes you’ll notice a contrast in colors between the two stars. This post will give you some tips on observing double stars with your eye alone, with binoculars and, if you want to take the plunge, with a small telescope. Read on, and learn to enjoy the sky’s delightful double stars!

Double star observing tips

To see double stars, Earth’s atmosphere needs to be still. A lot of motion in different layers of our atmosphere makes a star waver and dance. Astronomers will then say the seeing is poor. On nights of bad seeing, it can be very difficult for an observer with a telescope to “split” a binary pair into its two components. You might only see a single star. Whenever you’re looking toward a horizon, you’re looking through a thicker layer of atmosphere. So it’s better – when observing double stars – if your target is located near the sky’s zenith (overhead).

A couple of other observing factors contribute to whether you can see both components of a double star. Are you under a dark sky? How bright are the two stars you’re trying to see, that is, what are their magnitudes? Stars that shine at 5th or 6th magnitude are quite challenging but possible to observe. And lastly, how far apart are the stars? For anything closer together than 5 arcminutes you’ll probably want to try using binoculars.

Mizar and Alcor in the Big Dipper

For those new to double stars and new to observing the sky, it’s best to start with something simple. The optical double star Mizar and Alcor in the Big Dipper are a cinch to find. The Big Dipper asterism is a pattern that stands out due to its large size and bright stars. It’s visible year-round from Northern Hemisphere latitudes like those in the northern U.S. and Canada.

View at EarthSky Community Photos. | Susan Jensen captured this image on September 6, 2024, and wrote: “Right place, right time! Standing on a gravel road in the middle of nowhere, looking across a stubble field. This slow-moving, vibrant meteor stopped me in my tracks! I was shooting the Big Dipper with the shutter locked to catch multiple frames for stacking when this monster did a slow flyby. How lucky that I was able to capture it!” Thank you, Susan! Notice how you can see the 2 stars, Mizar and Alcor, snug together at the bend in the handle of the Big Dipper?

Seven stars make up the Big Dipper: four in the bowl and three in the handle. The middle of the three handle stars is the Mizar/Alcor pair. The stars appear about 12 arcminutes apart. So anyone with fair eyesight should be able to see them as two stars. Mizar is the brighter of the two, and Alcor is the dimmer one. Mizar shines at magnitude 2.2 from some 82 light-years away. And Alcor shines at magnitude 4 from about 81 light-years distant. These two stars are physically bound in space.

This chart of the Big Dipper includes a label for Mizar, while its companion star, Alcor, appears next to it without a label.

Mizar and Alcor with magnification

If you’re unable to split Mizar and Alcor with your eyes alone, go ahead and turn a pair of binoculars on them. Splitting Mizar and Alcor was a test of eyesight once upon a time. If you can’t see both without optical aid, maybe it’s time for a visit to the eye doctor?

To go deeper with these stars, look through a telescope and you’ll find that Mizar itself is a double star. The two parts of Mizar are 14 arcseconds apart. Fun fact: each of the two parts of Mizar are also double stars, making it a quadruple star system, not counting Alcor. Alcor is a double star, so in total, this is a sextuple star system.

Through a telescope, you can turn the double star Mizar and Alcor into a triple system. At left is Alcor, and at right is Mizar and its companion. Image via Nikolay Nikolov/ Wikimedia Commons (CC BY-SA 4.0).

View at EarthSky Community Photos. | Abdul Thomas captured this image through an 8″ telescope in Leeds, UK, on February 2, 2024. Abdul wrote: “Mizar and Alcor, a double star system in the northern constellation of Ursa Major the Great Bear. These two stars are clearly visible with the unaided eye and located on the handle of The Plough (Big Dipper) asterism.” Thank you, Abdul!

Scorpius holds 2 double star targets

Scorpius, a constellation best viewed in the Northern Hemisphere summer, has two pairs of double stars that you can try to separate using just your eyes. The easier target is Mu Scorpii. Its two components are a binary pair, one at magnitude 2.9 and one at 3.5. Use the chart here to find Mu and then let your eyes adjust to the dark to see if you can spot both the Mu stars. This pair is a little under 6 arcminutes apart.

If you can see them both without optical aid, try looking just below them for the two Zeta stars. These stars are merely an optical double. Zeta 1 is nearly 40 times farther away than Zeta 2. Zeta 2 is magnitude 3.6, just a hair dimmer than the dimmer member of Mu you spotted above. Zeta 1 is the hardest to spot at magnitude 4.7. If you need to use binoculars, go ahead and get a look, then try again without them. These two are about 6 1/2 arcminutes apart.

Mu Scorpii should not be a difficult pair to “split” with the unaided eye. But the Zeta Scorpii pair will be more challenging. Use the bright red star Antares as a guide to find Mu and Zeta.

Alpha Capricorni with or without binoculars

Like the double stars in Scorpius, the Alpha star in Capricornus will be visible to some people without any optical aid, while others will need to use a pair of binoculars. Alpha Capricorni is an optical double, that is, they only appear close together from our point of view. Alpha 1 shines at magnitude 4.2 and lies 633 light-years away. Its partner, Alpha 2, which also bears the name Algedi, shines at magnitude 3.5 and lies 107 light-years away. The pair are about 6 1/2 arcminutes apart.

Alpha Capricorni is a double star that some may see without optical aid while others will need to use binoculars.

Theta Tauri in the Bull’s head

Next up is Theta Tauri. You might be able to spy both parts of this double star without optical aid, but a steadily held pair of binoculars will make it easier. Theta Tauri is in the V-shape of Taurus’ head, near the brilliant, reddish Aldebaran. Theta 1 and Theta 2 lie about 5 1/2 arcminutes apart and shine at magnitudes 3.3 and 3.8.

When the two parts of the double star are similar in brightness or magnitude, they’re easier to split than when one is brighter than the other. Is Theta Tauri easier for you to see than Mu Scorpii?

Theta Tauri, the yellow and blue pair at center, lie close to brilliant Aldebaran in Taurus’ star cluster the Hyades. Image via NASA/ ESA/ STScI/ Wikimedia Commons (CC BY-SA 4.0).

Epsilon Lyrae, the famous Double Double

The Double Double – Epsilon Lyrae – is a system of two pairs of double stars in the summer constellation Lyra the Harp. But you can still see Lyra in the evening through November before it sets in the west. Lyra has many double stars. How many can you find if you sweep the area in binoculars?

The famous Double Double has stars around magnitude 5. The stars are simple to find, next to brilliant Vega. Epsilon 1 and Epsilon 2 are about 3 arcminutes apart, with the additional two parts of both Epsilon 1 and Epsilon 2 each being about 2 arcseconds apart. Look for the first pair of stars in binoculars. You may need a telescope to see each of those stars separate into two more stars.

The constellation Lyra the Harp. It’s made of a triangle and a parallelogram. Its brightest star is Vega. Look next to it for the famous Epsilon Lyrae, a double-double star, really 4 stars in all.

Epsilon Lyrae is the famous Double Double. Under magnification, you should be able to see the double stars split into double stars themselves. Image via Nikolay Nikolov/ Wikimedia Commons (CC BY-SA 4.0).

Colorful Albireo

Albireo – or Beta Cygni – has earned the nickname of the most beautiful double star in the heavens. This blue and yellow pair lies just 35 arcseconds apart from our point of view. Astronomers don’t yet know if this is a physically bound pair or just a line-of-sight coincidence. The two parts of Albireo shine at magnitudes 3.1 and 5.1. Albireo marks the head of Cygnus the Swan.

Albireo is a tighter pair discernible using larger binoculars or a small telescope. The star lies in the constellation Cygnus the Swan, opposite the bright star Deneb.

View at EarthSky Community Photos. | David Hoskin of Canada captured this on June 6, 2024, and wrote: “Albireo (Beta Cygni) is a colorful double star in the constellation Cygnus.” Thank you, David!

The Southern Hemisphere’s Alpha Centauri

The brightest star in Centaurus, found in the Southern Hemisphere, is not only a multiple star system but the closest star to Earth at 4.37 light-years. Alpha Centauri can be split into its components A and B. They are a true binary pair, being gravitationally bound.

Alpha Centauri – which is visible to the unaided eye as a single bright star – is a tighter pair that you can split using a small telescope. Use the bright constellation Crux, the Southern Cross, as a guide to find Alpha Centauri.

Using a 110mm refractor (a 4.3-inch telescope), the photographer captured this image of the double star Alpha Centauri in daylight. Image via Skatebiker/ Wikimedia Commons (CC BY-SA 4.0).

Once you get used to spotting double stars, you’ll find them in constellations everywhere. Good luck, and clear skies!

Bottom line: This double star observing guide gives you a range of choices for observing with your eyes alone. Or go further using binoculars or a telescope.

The post Double stars: How to find, observe and enjoy them first appeared on EarthSky.

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Anteaters are vacuum-like animals: Lifeform of the week

Our special fall crowd-funder is going on now. Please donate today to help EarthSky keep going!

What animal has four legs, a tail and a long trunk? The anteater! The elephant is not the only mammal that can boast a trunk. An anteater stands out with its large tail and elongated snoot. It also has one of the longest tongues in the world. Plus, these animals have an unusual way of eating and getting around. However, don’t be fooled, they are much more agile than they look.

What are anteaters?

Anteaters are mammals that inhabit Central and South America. They live in savannas, grasslands, swampy areas, dry forests and rainforests. Some look for food in open areas, and the rest in areas populated with trees. In fact, they are related to sloths, which live among tree branches.

There are only four species of anteaters in the world. They live between 15 and 20 years.

The giant anteater can exceed 6.5 feet (2 meters) in length and weigh up to 110 pounds (50 kg). It doesn’t climb trees, but rather sleeps curled up on the ground, with its trunk and body well covered by its long-haired tail, as if it was a blanket. If it’s cold, it looks for areas with tall grass or it can sleep in a burrow.

The smallest anteater is the pygmy anteater, which measures about 16 inches (40 cm) and weighs about 1 pound (0.5 kg). It lives and sleeps among tree branches and rarely ever touches the ground.

The southern tamandua and the northern tamandua anteaters live more in trees than on the ground. Of the two, the northern tamandua gets around a little better on the ground.

Anteaters are mammals that inhabit Central and South America. There are 4 species. This is the biggest one, the giant anteater. Image via Doug Morris/ Unsplash.

Not only elephants have trunks

As their name suggests, anteaters love ants and termites. In fact, those two insects are basically the only thing they eat. To reach them, they use their sharp front claws, which are hook-shaped, to open a hole in the nests or in rotten wood.

Once the hole is opened, they insert their long trunks and tongues to eat the insects. The tongue is long and narrow and has tiny spines positioned backwards. What’s more, it is saturated with a thick, sticky saliva that ants and termites stick to when the anteater introduces it into the nest, up to 150 times per minute.

Anteaters must eat quickly, because the ants fight back with painful stings, so they only spend a minute feasting on each mound. In addition, anteaters are smart about their hunting. They never destroy an ant or termite nest, so they can return to them in the future to feed again.

Anteaters eat lots of insects

Anteaters may be intelligent, but their heads are relatively small. However, their trunks can measure up to 24 inches (60 cm) in the biggest species, which is roughly 30% of their body length. Also, anteaters don’t have teeth.

Additionally, the nose and mouth are fused. So, they use their trunks to smell, breathe and eat. Since anteaters don’t see very well, their sense of smell is essential to locating food.

In a sense, they are like living vacuum cleaners. Besides eating from nests, they also tilt their heads towards the ground and sniff and suck any ants and termites that they find. In fact, they can eat up to 35,000 insects a day. Amazing!

Anteaters have long trunks and tongues to reach ants and termites in their nests and rotten wood. They also possess sharp front claws, that they use to open a hole in the nests. Image via Miguel Cuenca/ Pexels.

An unusual way of walking

The paws of anteaters also attract a lot of attention. All of them are strong, but the front ones have powerful claws at the end. Other than the giant anteaters, they can easily climb trees. They use their claws to move among tree branches, with help from their tails, since they are flexible and can curl around branches.

Additionally, those that move on the ground don’t walk on their claws, because they face backwards and obliquely. Instead, they walk on the side of their paws, which have a pad, like that of a cat.

Their hind legs have five fingers with nails, so anteaters use their whole back feet soles to walk.

A southern tamandua. Anteaters that walk on the ground walk on the side of their paws. Image via Marcelo Amantino/ Pexels.

They are peaceful animals

Anteaters are most active at night. However, they will venture out to eat during the day if they are away from civilization. In general, they are peaceful animals that avoid conflict.

They sleep up to 15 hours a day. In fact, they sleep curled up and covered with their tails in secluded places. Giant anteaters can fall asleep instantly out in the open. Yet even pumas and jaguars think twice before attacking them. That’s because giant anteaters have an impressive weapon: 4 inches (10 cm) of strong claws.

Unfortunately, giant anteater pups and other smaller species are more vulnerable. However, their sizes don’t prevent them from defending themselves. Cornered anteaters stand on their hind legs, using their tails to maintain balance, and lash out at their attackers with those dangerous claws. The smallest anteaters have been seen hanging upside down, holding onto branches with their tails, and displaying their claws.

So, tails are important. They are muscular and flexible, with short hair. Giant anteaters, however, have strong, rigid tails densely covered with long, coarse hair.

A northen tamandua. These peaceful animals avoid conflict. They sleep around 15 hours a day. Some of them sleep among tree branches, and others on the ground. Image via Tomáš Malík/ Unsplash.

Baby anteaters

Anteaters are quite solitary and mate once or twice a year. Females typically have a single pup, which they gestate for approximately 190 days, ensuring that it is well equipped for survival.

Immediately after birth, the baby anteater clings to its mother’s back and remains there for about a year.

A southern tamandua and her pup. Females typically have a single pup, which clings to its mother’s back and remains there for about a year. Image via Últimos Refugios/ iNaturalist (CC BY-NC 4.0).

Other anteater facts

Anteaters have a highly developed sense of smell, up to 40 times stronger than humans.

Their consumption of ants and termites in a single day plays a crucial role in regulating insect populations.

Their slow metabolism allows them to extract maximum energy from their prey, essential for survival in food-scarce environments.

There are many interesting things about these mammals. For example, their sense of smell is 40 times stronger than ours. Image via Sean P. Twomey/ Pexels.

They can move around their environment with surprising agility and are good swimmers.

Anteaters communicate through scent marking and they can emit a high-pitched, shrill grunt.

They are related to armadillos.

It may not look like it, but these animals are quite agile and also good swimmers. Image via
Claudio Consonni/ iNaturalist (CC BY-NC 4.0).

More photos

A pygmy anteater. They rarely touch the ground and they are the smallest anteater. Image via Jerome Foster/ iNaturalist (CC BY-NC-ND 4.0).

Another pygmy anteater. Image via Anthony Ramírez Murillo/ iNaturalist (CC BY-NC 4.0).

A northern tamandua. Anteaters that climb trees have strong, flexible tails. Image via Mateo Hernandez Schmidt/ iNaturalist (CC BY-NC-SA 4.0).

Bottom line: Anteaters are known for their vacuum-like feeding habits, using their long trunks and tongues to consume up to 35,000 ants and termites daily. They have strong claws and flexible tails, which help them navigate their environments.

Ants, little but tough: Lifeform of the week

Sloths are our calm and smiley lifeform of the week

The post Anteaters are vacuum-like animals: Lifeform of the week first appeared on EarthSky.

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Our special fall crowd-funder is going on now. Please donate today to help EarthSky keep going!

What animal has four legs, a tail and a long trunk? The anteater! The elephant is not the only mammal that can boast a trunk. An anteater stands out with its large tail and elongated snoot. It also has one of the longest tongues in the world. Plus, these animals have an unusual way of eating and getting around. However, don’t be fooled, they are much more agile than they look.

What are anteaters?

Anteaters are mammals that inhabit Central and South America. They live in savannas, grasslands, swampy areas, dry forests and rainforests. Some look for food in open areas, and the rest in areas populated with trees. In fact, they are related to sloths, which live among tree branches.

There are only four species of anteaters in the world. They live between 15 and 20 years.

The giant anteater can exceed 6.5 feet (2 meters) in length and weigh up to 110 pounds (50 kg). It doesn’t climb trees, but rather sleeps curled up on the ground, with its trunk and body well covered by its long-haired tail, as if it was a blanket. If it’s cold, it looks for areas with tall grass or it can sleep in a burrow.

The smallest anteater is the pygmy anteater, which measures about 16 inches (40 cm) and weighs about 1 pound (0.5 kg). It lives and sleeps among tree branches and rarely ever touches the ground.

The southern tamandua and the northern tamandua anteaters live more in trees than on the ground. Of the two, the northern tamandua gets around a little better on the ground.

Anteaters are mammals that inhabit Central and South America. There are 4 species. This is the biggest one, the giant anteater. Image via Doug Morris/ Unsplash.

Not only elephants have trunks

As their name suggests, anteaters love ants and termites. In fact, those two insects are basically the only thing they eat. To reach them, they use their sharp front claws, which are hook-shaped, to open a hole in the nests or in rotten wood.

Once the hole is opened, they insert their long trunks and tongues to eat the insects. The tongue is long and narrow and has tiny spines positioned backwards. What’s more, it is saturated with a thick, sticky saliva that ants and termites stick to when the anteater introduces it into the nest, up to 150 times per minute.

Anteaters must eat quickly, because the ants fight back with painful stings, so they only spend a minute feasting on each mound. In addition, anteaters are smart about their hunting. They never destroy an ant or termite nest, so they can return to them in the future to feed again.

Anteaters eat lots of insects

Anteaters may be intelligent, but their heads are relatively small. However, their trunks can measure up to 24 inches (60 cm) in the biggest species, which is roughly 30% of their body length. Also, anteaters don’t have teeth.

Additionally, the nose and mouth are fused. So, they use their trunks to smell, breathe and eat. Since anteaters don’t see very well, their sense of smell is essential to locating food.

In a sense, they are like living vacuum cleaners. Besides eating from nests, they also tilt their heads towards the ground and sniff and suck any ants and termites that they find. In fact, they can eat up to 35,000 insects a day. Amazing!

Anteaters have long trunks and tongues to reach ants and termites in their nests and rotten wood. They also possess sharp front claws, that they use to open a hole in the nests. Image via Miguel Cuenca/ Pexels.

An unusual way of walking

The paws of anteaters also attract a lot of attention. All of them are strong, but the front ones have powerful claws at the end. Other than the giant anteaters, they can easily climb trees. They use their claws to move among tree branches, with help from their tails, since they are flexible and can curl around branches.

Additionally, those that move on the ground don’t walk on their claws, because they face backwards and obliquely. Instead, they walk on the side of their paws, which have a pad, like that of a cat.

Their hind legs have five fingers with nails, so anteaters use their whole back feet soles to walk.

A southern tamandua. Anteaters that walk on the ground walk on the side of their paws. Image via Marcelo Amantino/ Pexels.

They are peaceful animals

Anteaters are most active at night. However, they will venture out to eat during the day if they are away from civilization. In general, they are peaceful animals that avoid conflict.

They sleep up to 15 hours a day. In fact, they sleep curled up and covered with their tails in secluded places. Giant anteaters can fall asleep instantly out in the open. Yet even pumas and jaguars think twice before attacking them. That’s because giant anteaters have an impressive weapon: 4 inches (10 cm) of strong claws.

Unfortunately, giant anteater pups and other smaller species are more vulnerable. However, their sizes don’t prevent them from defending themselves. Cornered anteaters stand on their hind legs, using their tails to maintain balance, and lash out at their attackers with those dangerous claws. The smallest anteaters have been seen hanging upside down, holding onto branches with their tails, and displaying their claws.

So, tails are important. They are muscular and flexible, with short hair. Giant anteaters, however, have strong, rigid tails densely covered with long, coarse hair.

A northen tamandua. These peaceful animals avoid conflict. They sleep around 15 hours a day. Some of them sleep among tree branches, and others on the ground. Image via Tomáš Malík/ Unsplash.

Baby anteaters

Anteaters are quite solitary and mate once or twice a year. Females typically have a single pup, which they gestate for approximately 190 days, ensuring that it is well equipped for survival.

Immediately after birth, the baby anteater clings to its mother’s back and remains there for about a year.

A southern tamandua and her pup. Females typically have a single pup, which clings to its mother’s back and remains there for about a year. Image via Últimos Refugios/ iNaturalist (CC BY-NC 4.0).

Other anteater facts

Anteaters have a highly developed sense of smell, up to 40 times stronger than humans.

Their consumption of ants and termites in a single day plays a crucial role in regulating insect populations.

Their slow metabolism allows them to extract maximum energy from their prey, essential for survival in food-scarce environments.

There are many interesting things about these mammals. For example, their sense of smell is 40 times stronger than ours. Image via Sean P. Twomey/ Pexels.

They can move around their environment with surprising agility and are good swimmers.

Anteaters communicate through scent marking and they can emit a high-pitched, shrill grunt.

They are related to armadillos.

It may not look like it, but these animals are quite agile and also good swimmers. Image via
Claudio Consonni/ iNaturalist (CC BY-NC 4.0).

More photos

A pygmy anteater. They rarely touch the ground and they are the smallest anteater. Image via Jerome Foster/ iNaturalist (CC BY-NC-ND 4.0).

Another pygmy anteater. Image via Anthony Ramírez Murillo/ iNaturalist (CC BY-NC 4.0).

A northern tamandua. Anteaters that climb trees have strong, flexible tails. Image via Mateo Hernandez Schmidt/ iNaturalist (CC BY-NC-SA 4.0).

Bottom line: Anteaters are known for their vacuum-like feeding habits, using their long trunks and tongues to consume up to 35,000 ants and termites daily. They have strong claws and flexible tails, which help them navigate their environments.

Ants, little but tough: Lifeform of the week

Sloths are our calm and smiley lifeform of the week

The post Anteaters are vacuum-like animals: Lifeform of the week first appeared on EarthSky.

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Hurricane Milton headed for Florida’s west coast

This is the view of Hurricane Milton from space on Monday morning, October 7, 2024. Milton underwent rapid intensification and is poised to hit Florida’s west coast late Wednesday or early Thursday. Image via NOAA.

Hurricane Milton threatens Florida’s west coast

Hurricane Milton, which sprang to life in the western corner of the Gulf of Mexico, has rapidly intensified as it barrels toward the west coast of Florida. As of Monday morning, its maximum sustained winds were 155 miles per hour, a strong Category 4. The exact track of the hurricane is still uncertain, but it will brush past the Yucatan before coming onshore late Wednesday or early Thursday around the Tampa Bay area.

The National Weather Service said that areas where Milton comes ashore should expect rainfall amounts of 5 to 10 inches, with localized totals up to 15 inches.

As Jeff Masters wrote in Yale’s Climate Connections blog:

The most vulnerable metropolitan area in the U.S. to storm surge damage is Tampa/St. Petersburg. That’s according to a 2015 report by Karen Clark & Company, Most Vulnerable US Cities to Storm Surge Flooding. Their 1-in-100-year storm (with a 1% chance of occurring in any given year) was a strong Category 4 hurricane with 150 mph (240 km/h) winds. Such a storm striking just north of Tampa Bay could be expected to cause $230 billion in damage (2024 USD) – just from the storm surge.

There are some 3.5 million residents in the four-county region surrounding Tampa Bay.

#HurricaneMilton and #Florida housing growth since 1940. #disaster #FLwx #ExpandingBullsEye pic.twitter.com/vih7u3xjbc

— Stephen M. Strader (@StephenMStrader) October 7, 2024

Rapid intensification of Hurricane Milton

Meteorologists define rapid intensification as when a hurricane undergoes an increase in wind speeds of 35 mph in 24 hours. From Sunday to Monday, Hurricane Milton increased its wind speeds by 85 mph in 24 hours. Hurricane Milton could become a Category 5 hurricane, but it should weaken before it comes onshore on Florida’s west coast Wednesday or Thursday. Unfortunately, the storm surge is already built up. Think of it in comparison to Hurricane Katrina in 2005. It was a Category 5 in the Gulf but weakened to Category 3 went it came onshore. However, it still brought with it the storm surge of a Category 5 storm in the New Orleans area.

This was the likely path of Hurricane Milton as of Monday morning, October 7, 2024. Image via NHC/ NOAA.

For the first time in recorded history, the Atlantic basin has three active hurricanes in October or later.

H/t @philklotzbach for the fascinating statistic. pic.twitter.com/dohSvl8bFG

— CIRA (@CIRA_CSU) October 6, 2024

Prepare now!

Residents please check your emergency plans, evacuation zone, and be prepared to act quickly as additional storm information is updated.

Please look over these tips on securing your home from Pinellas County Government and visit https://t.co/xqGZutEAFD for more tips. pic.twitter.com/pZ5qCjFAkX

— Pinellas County Sheriff's Office (@SheriffPinellas) October 7, 2024

?? A #MandatoryEvacuation order in Hillsborough County has been issued for zones A and B beginning at 2:30 p.m. today.

Those living in mobile and manufactured homes, no matter their zone, are under a mandatory evacuation.

?? Find more info here: https://t.co/xpdIuvGfkV pic.twitter.com/DTQk2dHMw1

— Hillsborough County (@HillsboroughFL) October 7, 2024

You don't see this every day. These forecast wave heights around #Milton are terrifying. pic.twitter.com/TH0lMUKpzm

— Brian McNoldy (@BMcNoldy) October 7, 2024

Delaying Europa Clipper

The mission to Jupiter’s moon Europa – known as Europa Clipper – was supposed to launch from Cape Canaveral on October 10. Due to Milton, that launch is postponed, with no rescheduled date yet. However, due to planetary alignments that the mission must make use of, the launch window only extends to the end of October.

Meanwhile, another mission – Hera, the “crime scene investigator” for the Dart mission to Dimorphos – managed to launch ahead of the storm on Monday.

Hurricane Helene

Hurricane Helene recently came ashore on September 26, 2024, in Florida’s Big Bend region, north of Tampa. But that storm also impacted the Tampa area. Many of the surrounding communities had record storm surges in that storm. Milton is poised to strike the area more directly.

But exactly where Milton comes onshore will make a big difference. The farther south the storm hits Florida, the better it will be for the Tampa area. That’s because the northern winds bring less storm surge than winds on the south side of the hurricane. Of course, the farther south it hits, the worse it will be for areas around Fort Myers, which were badly damaged in Hurricane Ian in 2022.

Dump trucks getting a police escort as Pinellas County rushes to remove piles of debris from Helene before Cat. 4 Hurricane Milton hits on Wednesday with another big surge (8-12') and wind gusts >100 MPH.
We're live on @foxweather pic.twitter.com/ebYydJvgpQ

— Mike Seidel (@mikeseidel) October 7, 2024

Bottom line: Hurricane Milton underwent rapid intensification from Sunday to Monday. It was a strong Category 4 storm Monday morning, brushing past the Yucatan on its way to Florida.

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This is the view of Hurricane Milton from space on Monday morning, October 7, 2024. Milton underwent rapid intensification and is poised to hit Florida’s west coast late Wednesday or early Thursday. Image via NOAA.

Hurricane Milton threatens Florida’s west coast

Hurricane Milton, which sprang to life in the western corner of the Gulf of Mexico, has rapidly intensified as it barrels toward the west coast of Florida. As of Monday morning, its maximum sustained winds were 155 miles per hour, a strong Category 4. The exact track of the hurricane is still uncertain, but it will brush past the Yucatan before coming onshore late Wednesday or early Thursday around the Tampa Bay area.

The National Weather Service said that areas where Milton comes ashore should expect rainfall amounts of 5 to 10 inches, with localized totals up to 15 inches.

As Jeff Masters wrote in Yale’s Climate Connections blog:

The most vulnerable metropolitan area in the U.S. to storm surge damage is Tampa/St. Petersburg. That’s according to a 2015 report by Karen Clark & Company, Most Vulnerable US Cities to Storm Surge Flooding. Their 1-in-100-year storm (with a 1% chance of occurring in any given year) was a strong Category 4 hurricane with 150 mph (240 km/h) winds. Such a storm striking just north of Tampa Bay could be expected to cause $230 billion in damage (2024 USD) – just from the storm surge.

There are some 3.5 million residents in the four-county region surrounding Tampa Bay.

#HurricaneMilton and #Florida housing growth since 1940. #disaster #FLwx #ExpandingBullsEye pic.twitter.com/vih7u3xjbc

— Stephen M. Strader (@StephenMStrader) October 7, 2024

Rapid intensification of Hurricane Milton

Meteorologists define rapid intensification as when a hurricane undergoes an increase in wind speeds of 35 mph in 24 hours. From Sunday to Monday, Hurricane Milton increased its wind speeds by 85 mph in 24 hours. Hurricane Milton could become a Category 5 hurricane, but it should weaken before it comes onshore on Florida’s west coast Wednesday or Thursday. Unfortunately, the storm surge is already built up. Think of it in comparison to Hurricane Katrina in 2005. It was a Category 5 in the Gulf but weakened to Category 3 went it came onshore. However, it still brought with it the storm surge of a Category 5 storm in the New Orleans area.

This was the likely path of Hurricane Milton as of Monday morning, October 7, 2024. Image via NHC/ NOAA.

For the first time in recorded history, the Atlantic basin has three active hurricanes in October or later.

H/t @philklotzbach for the fascinating statistic. pic.twitter.com/dohSvl8bFG

— CIRA (@CIRA_CSU) October 6, 2024

Prepare now!

Residents please check your emergency plans, evacuation zone, and be prepared to act quickly as additional storm information is updated.

Please look over these tips on securing your home from Pinellas County Government and visit https://t.co/xqGZutEAFD for more tips. pic.twitter.com/pZ5qCjFAkX

— Pinellas County Sheriff's Office (@SheriffPinellas) October 7, 2024

?? A #MandatoryEvacuation order in Hillsborough County has been issued for zones A and B beginning at 2:30 p.m. today.

Those living in mobile and manufactured homes, no matter their zone, are under a mandatory evacuation.

?? Find more info here: https://t.co/xpdIuvGfkV pic.twitter.com/DTQk2dHMw1

— Hillsborough County (@HillsboroughFL) October 7, 2024

You don't see this every day. These forecast wave heights around #Milton are terrifying. pic.twitter.com/TH0lMUKpzm

— Brian McNoldy (@BMcNoldy) October 7, 2024

Delaying Europa Clipper

The mission to Jupiter’s moon Europa – known as Europa Clipper – was supposed to launch from Cape Canaveral on October 10. Due to Milton, that launch is postponed, with no rescheduled date yet. However, due to planetary alignments that the mission must make use of, the launch window only extends to the end of October.

Meanwhile, another mission – Hera, the “crime scene investigator” for the Dart mission to Dimorphos – managed to launch ahead of the storm on Monday.

Hurricane Helene

Hurricane Helene recently came ashore on September 26, 2024, in Florida’s Big Bend region, north of Tampa. But that storm also impacted the Tampa area. Many of the surrounding communities had record storm surges in that storm. Milton is poised to strike the area more directly.

But exactly where Milton comes onshore will make a big difference. The farther south the storm hits Florida, the better it will be for the Tampa area. That’s because the northern winds bring less storm surge than winds on the south side of the hurricane. Of course, the farther south it hits, the worse it will be for areas around Fort Myers, which were badly damaged in Hurricane Ian in 2022.

Dump trucks getting a police escort as Pinellas County rushes to remove piles of debris from Helene before Cat. 4 Hurricane Milton hits on Wednesday with another big surge (8-12') and wind gusts >100 MPH.
We're live on @foxweather pic.twitter.com/ebYydJvgpQ

— Mike Seidel (@mikeseidel) October 7, 2024

Bottom line: Hurricane Milton underwent rapid intensification from Sunday to Monday. It was a strong Category 4 storm Monday morning, brushing past the Yucatan on its way to Florida.

The post Hurricane Milton headed for Florida’s west coast first appeared on EarthSky.

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Dolphins make smile-like expressions during play

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Bottlenose dolphins use an open-mouth facial expression, resembling a smile, during playful interactions with other dolphins.

They can mimic that facial expression in playmates that also display it.

This facial expression shapes complex social interactions, similar to other social mammals.

Dolphins ‘smile’ during play

Dolphins delight us with their playful frolicking, a behavior we find endearingly relatable. Scientists recently studied captive bottlenose dolphins to learn more about how they interact with each other. They noticed the dolphins, while playing with each other, communicated using an open-mouth facial expression. That expression resembled what we humans might perceive as a “smile.”

The scientists published their findings in the peer-reviewed journal iScience on October 2, 2024.

Elisabetta Palagi of the University of Pisa in Italy is a paper co-author. In a statement published in EurekAlert, she said:

We’ve uncovered the presence of a distinct facial display, the open mouth, in bottlenose dolphins, and we showed that dolphins are also able to mirror others’ facial expression. Open-mouth signals and rapid mimicry appear repeatedly across the mammal family tree, which suggests that visual communication has played a crucial role in shaping complex social interactions, not only in dolphins but in many species over time.

Here’s one of the dolphins in the study showing its open-mouth “smile.” Image via ZooMarine, Italy/ EurekAlert.

Playful facial expressions in mammals

Playfulness is a trait exhibited by many mammals. Broadly speaking, the definition of play is spontaneous open-ended actions that do not have an obvious practical function, carried out in a stress-free setting. We humans associate play with joy and fun.

However, we don’t know if dolphins have similar emotions to humans during play. All scientists can do is observe their behavior. For dolphins, play activities include acrobatics, playing with objects, chasing each other, surfing and even play-fighting. Moreover, dolphins exhibit playful behavior at all ages. It starts at a young age, between a calf and mother, before the calf expands its social network to play with others in its group.

Play also involves complex communication, since certain play actions may also be used in an aggressive context. Some mammals, the scientists said, are known to use distinct facial expressions during playtime to indicate their mood. One expression is a relaxed open mouth, seen in playful social mammals.

Palagi commented:

The open mouth gesture likely evolved from the biting action, breaking down the biting sequence to leave only the “intention to bite” without contact. The relaxed open mouth, seen in social carnivores, monkeys’ play faces, and even human laughter, is a universal sign of playfulness, helping animals – and us – signal fun and avoid conflict.

Studying captive dolphins at play

The scientists studied over 80 hours of video of captive dolphins. They observed how the dolphins interacted with each other and how they interacted with their human trainers.

Dolphins playing with each other, the researchers noticed, often displayed an open-mouth expression. But, for the most part, dolphins did not display the open-mouth expression when playing alone or with a trainer.

A dolphin was more likely to display the open mouth expression when the other dolphin playmate was within its sight. Perhaps it was a way to get the attention of its companion.

And notably, the playmate would respond, mimicking the same open-mouth expression, about 1/3 of the time.

Palagi remarked:

Some may argue that dolphins are merely mimicking each other’s open-mouth expressions by chance, given they’re often involved in the same activity or context, but this doesn’t explain why the probability of mimicking another dolphin’s open mouth within 1 second is 13 times higher when the receiver actually sees the original expression. This rate of mimicry in dolphins is consistent with what’s been observed in certain carnivores, such as meerkats and sun bears.

More dolphin playtime studies to come

The researchers would like to continue their work by recording sounds the dolphins make when they play.

Paper co-author Livio Favaro of the University of Turin said:

Future research should dive into eye-tracking to explore how dolphins see their world and utilize acoustic signals in their multimodal communication during play. Dolphins have developed one of the most intricate vocal systems in the animal world, but sound can also expose them to predators or eavesdroppers. When dolphins play together, a mix of whistling and visual cues helps them cooperate and achieve goals, a strategy particularly useful during social play when they’re less on guard for predators.

Bottom line: Bottlenose dolphins use an open-mouth facial expression when playing with each other, resembling what humans might perceive as a “smile.”

Source: Smiling underwater: Exploring playful signals and rapid mimicry in bottlenose dolphins

Via EurekAlert

Read more: Dolphins may use whistles like humans use names

The post Dolphins make smile-like expressions during play first appeared on EarthSky.

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Our special fall crowd-funder is going on now. Please donate today to help EarthSky keep going!

Bottlenose dolphins use an open-mouth facial expression, resembling a smile, during playful interactions with other dolphins.

They can mimic that facial expression in playmates that also display it.

This facial expression shapes complex social interactions, similar to other social mammals.

Dolphins ‘smile’ during play

Dolphins delight us with their playful frolicking, a behavior we find endearingly relatable. Scientists recently studied captive bottlenose dolphins to learn more about how they interact with each other. They noticed the dolphins, while playing with each other, communicated using an open-mouth facial expression. That expression resembled what we humans might perceive as a “smile.”

The scientists published their findings in the peer-reviewed journal iScience on October 2, 2024.

Elisabetta Palagi of the University of Pisa in Italy is a paper co-author. In a statement published in EurekAlert, she said:

We’ve uncovered the presence of a distinct facial display, the open mouth, in bottlenose dolphins, and we showed that dolphins are also able to mirror others’ facial expression. Open-mouth signals and rapid mimicry appear repeatedly across the mammal family tree, which suggests that visual communication has played a crucial role in shaping complex social interactions, not only in dolphins but in many species over time.

Here’s one of the dolphins in the study showing its open-mouth “smile.” Image via ZooMarine, Italy/ EurekAlert.

Playful facial expressions in mammals

Playfulness is a trait exhibited by many mammals. Broadly speaking, the definition of play is spontaneous open-ended actions that do not have an obvious practical function, carried out in a stress-free setting. We humans associate play with joy and fun.

However, we don’t know if dolphins have similar emotions to humans during play. All scientists can do is observe their behavior. For dolphins, play activities include acrobatics, playing with objects, chasing each other, surfing and even play-fighting. Moreover, dolphins exhibit playful behavior at all ages. It starts at a young age, between a calf and mother, before the calf expands its social network to play with others in its group.

Play also involves complex communication, since certain play actions may also be used in an aggressive context. Some mammals, the scientists said, are known to use distinct facial expressions during playtime to indicate their mood. One expression is a relaxed open mouth, seen in playful social mammals.

Palagi commented:

The open mouth gesture likely evolved from the biting action, breaking down the biting sequence to leave only the “intention to bite” without contact. The relaxed open mouth, seen in social carnivores, monkeys’ play faces, and even human laughter, is a universal sign of playfulness, helping animals – and us – signal fun and avoid conflict.

Studying captive dolphins at play

The scientists studied over 80 hours of video of captive dolphins. They observed how the dolphins interacted with each other and how they interacted with their human trainers.

Dolphins playing with each other, the researchers noticed, often displayed an open-mouth expression. But, for the most part, dolphins did not display the open-mouth expression when playing alone or with a trainer.

A dolphin was more likely to display the open mouth expression when the other dolphin playmate was within its sight. Perhaps it was a way to get the attention of its companion.

And notably, the playmate would respond, mimicking the same open-mouth expression, about 1/3 of the time.

Palagi remarked:

Some may argue that dolphins are merely mimicking each other’s open-mouth expressions by chance, given they’re often involved in the same activity or context, but this doesn’t explain why the probability of mimicking another dolphin’s open mouth within 1 second is 13 times higher when the receiver actually sees the original expression. This rate of mimicry in dolphins is consistent with what’s been observed in certain carnivores, such as meerkats and sun bears.

More dolphin playtime studies to come

The researchers would like to continue their work by recording sounds the dolphins make when they play.

Paper co-author Livio Favaro of the University of Turin said:

Future research should dive into eye-tracking to explore how dolphins see their world and utilize acoustic signals in their multimodal communication during play. Dolphins have developed one of the most intricate vocal systems in the animal world, but sound can also expose them to predators or eavesdroppers. When dolphins play together, a mix of whistling and visual cues helps them cooperate and achieve goals, a strategy particularly useful during social play when they’re less on guard for predators.

Bottom line: Bottlenose dolphins use an open-mouth facial expression when playing with each other, resembling what humans might perceive as a “smile.”

Source: Smiling underwater: Exploring playful signals and rapid mimicry in bottlenose dolphins

Via EurekAlert

Read more: Dolphins may use whistles like humans use names

The post Dolphins make smile-like expressions during play first appeared on EarthSky.

from EarthSky https://ift.tt/RgIft10

1st planet orbiting a sunlike star discovered 29 years ago

Astronomers discovered the 1st planet orbiting a sunlike star in 1995. Here is a comparison showing an artists’ conception of 51 Pegasi b to Jupiter and 51 Pegasi to the sun. Image via NASA Exoplanet Exploration.

51 Pegasi b: 1st planet found orbiting a sunlike star

October 6, 1995: On this date, astronomers Michel Mayor and Didier Queloz announced the discovery of the first planet in orbit around a distant sunlike star. They later published their finding in the journal Nature, in a paper titled simply A Jupiter-Mass Companion to a Solar-type Star.

The star was 51 Pegasi, located about 50 light-years away in the constellation Pegasus the Flying Horse. Astronomers officially designated the new planet as 51 Pegasi b, in accordance with nomenclature already decided upon for extrasolar planets. The b means that this planet was the first discovered orbiting its parent star. If additional planets are ever found for the star 51 Pegasi, they’ll be designated c, d, e, f, and so on. So far, this planet is the only one known in this system.

Other names for the planet 51 Pegasi b

Astronomers call 51 Pegasi b by other names. The astronomer Geoffrey Marcy dubbed it Bellerophon. Marcy helped confirm its existence and was following the convention of naming planets after Greek and Roman mythological figures. In fact, Bellerophon was a figure from Greek mythology who rode the winged horse Pegasus. Later, in the course of its NameExoWorlds contest, the International Astronomical Union named this planet Dimidium. Which is Latin for half, referring to its mass of at least half the mass of Jupiter.

Also, astronomers consider 51 Pegasi b the prototype for the class of planets astronomers call hot Jupiters.

51 Pegasi b was the first of thousands of exoplanets

While 51 Pegasi b was the first, we now know there are thousands of exoplanets. As of October 2024, astronomers have confirmed more than 5,500 exoplanets.

But 51 Pegasi b will always be the first known exoplanet to orbit a star like our sun.

This day on October 6, 1995 – The first planet orbiting another sun, 51 Pegasi b, is discovered. pic.twitter.com/oaNEoexHLa

— World of Engineering (@engineers_feed) October 6, 2020

What we know about 51 Pegasi b

What do we know today of 51 Pegasi b, a world whose place in astronomical history is so secure? Its mass is about half that of Jupiter. It’s thought to have a larger diameter than Jupiter (the biggest planet in our solar system), despite its smaller mass. 51 Pegasi b orbits very close to its parent star, requiring only four days to orbit its star. As you know, the Earth orbits the sun in 365 days. It takes Jupiter 12 years to complete one orbit. In other words, 51 Pegasi b orbits very close to its star.

It’s also known that this planet is tidally locked to its star, much as our moon is tidally locked to Earth. So, the planet is always presenting the same face to Pegasi 51. Plus, it’s what’s known today as a hot Jupiter.

By the way, detailed pictures you see of exoplanets, such as the one at the top of this post, are always artists’ concepts. Even the largest earthly telescopes can’t see planets orbiting distant suns in anything like this amount of detail. At best, through earthly telescopes, they look like dots. Still, analyzing exoplanets – their atmospheres, for example, and their potential for life – is a major priority for NASA and for many astronomers in the years ahead. In fact, the Webb telescope has already imaged an exoplanet.

Searching for exoplanets is challenging

Consider that, before 51 Pegasi b, the search for exoplanets – worlds beyond our own solar system – was exceedingly difficult. Once astronomers began in earnest to search for them, they searched for decades before finding any. In nearly all cases, the light of their parent stars hides any exoplanets orbiting them. So, astronomers had to develop clever technologies to discover them. As with many extrasolar planets, astronomers used the radial velocity method to locate Pegasi 51 b. Click here to learn more about how astronomers find exoplanets.

View larger. | The momentous discovery of the 1st exoplanet around a sunlike star – 51 Pegasi b – caused astronomers to question what they knew of our universe. It launched further searches for new worlds. Infographic via NASA/ JPL-Caltech.

Bottom line: On October 6, 1995, astronomers Michel Mayor and Didier Queloz announced the discovery of the first planet orbiting around a distant sunlike star. This planet is 51 Pegasi b.

Read more: Planet discovered orbiting closest single star to sun

The post 1st planet orbiting a sunlike star discovered 29 years ago first appeared on EarthSky.

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Astronomers discovered the 1st planet orbiting a sunlike star in 1995. Here is a comparison showing an artists’ conception of 51 Pegasi b to Jupiter and 51 Pegasi to the sun. Image via NASA Exoplanet Exploration.

51 Pegasi b: 1st planet found orbiting a sunlike star

October 6, 1995: On this date, astronomers Michel Mayor and Didier Queloz announced the discovery of the first planet in orbit around a distant sunlike star. They later published their finding in the journal Nature, in a paper titled simply A Jupiter-Mass Companion to a Solar-type Star.

The star was 51 Pegasi, located about 50 light-years away in the constellation Pegasus the Flying Horse. Astronomers officially designated the new planet as 51 Pegasi b, in accordance with nomenclature already decided upon for extrasolar planets. The b means that this planet was the first discovered orbiting its parent star. If additional planets are ever found for the star 51 Pegasi, they’ll be designated c, d, e, f, and so on. So far, this planet is the only one known in this system.

Other names for the planet 51 Pegasi b

Astronomers call 51 Pegasi b by other names. The astronomer Geoffrey Marcy dubbed it Bellerophon. Marcy helped confirm its existence and was following the convention of naming planets after Greek and Roman mythological figures. In fact, Bellerophon was a figure from Greek mythology who rode the winged horse Pegasus. Later, in the course of its NameExoWorlds contest, the International Astronomical Union named this planet Dimidium. Which is Latin for half, referring to its mass of at least half the mass of Jupiter.

Also, astronomers consider 51 Pegasi b the prototype for the class of planets astronomers call hot Jupiters.

51 Pegasi b was the first of thousands of exoplanets

While 51 Pegasi b was the first, we now know there are thousands of exoplanets. As of October 2024, astronomers have confirmed more than 5,500 exoplanets.

But 51 Pegasi b will always be the first known exoplanet to orbit a star like our sun.

This day on October 6, 1995 – The first planet orbiting another sun, 51 Pegasi b, is discovered. pic.twitter.com/oaNEoexHLa

— World of Engineering (@engineers_feed) October 6, 2020

What we know about 51 Pegasi b

What do we know today of 51 Pegasi b, a world whose place in astronomical history is so secure? Its mass is about half that of Jupiter. It’s thought to have a larger diameter than Jupiter (the biggest planet in our solar system), despite its smaller mass. 51 Pegasi b orbits very close to its parent star, requiring only four days to orbit its star. As you know, the Earth orbits the sun in 365 days. It takes Jupiter 12 years to complete one orbit. In other words, 51 Pegasi b orbits very close to its star.

It’s also known that this planet is tidally locked to its star, much as our moon is tidally locked to Earth. So, the planet is always presenting the same face to Pegasi 51. Plus, it’s what’s known today as a hot Jupiter.

By the way, detailed pictures you see of exoplanets, such as the one at the top of this post, are always artists’ concepts. Even the largest earthly telescopes can’t see planets orbiting distant suns in anything like this amount of detail. At best, through earthly telescopes, they look like dots. Still, analyzing exoplanets – their atmospheres, for example, and their potential for life – is a major priority for NASA and for many astronomers in the years ahead. In fact, the Webb telescope has already imaged an exoplanet.

Searching for exoplanets is challenging

Consider that, before 51 Pegasi b, the search for exoplanets – worlds beyond our own solar system – was exceedingly difficult. Once astronomers began in earnest to search for them, they searched for decades before finding any. In nearly all cases, the light of their parent stars hides any exoplanets orbiting them. So, astronomers had to develop clever technologies to discover them. As with many extrasolar planets, astronomers used the radial velocity method to locate Pegasi 51 b. Click here to learn more about how astronomers find exoplanets.

View larger. | The momentous discovery of the 1st exoplanet around a sunlike star – 51 Pegasi b – caused astronomers to question what they knew of our universe. It launched further searches for new worlds. Infographic via NASA/ JPL-Caltech.

Bottom line: On October 6, 1995, astronomers Michel Mayor and Didier Queloz announced the discovery of the first planet orbiting around a distant sunlike star. This planet is 51 Pegasi b.

Read more: Planet discovered orbiting closest single star to sun

The post 1st planet orbiting a sunlike star discovered 29 years ago first appeared on EarthSky.

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