Tonight, if you have a dark sky, try star-hopping to the Andromeda galaxy from the constellation Cassiopeia the Queen. If your sky is truly dark, you might even spot this hazy patch of light with no optical aid, as the ancient stargazers did before the days of light pollution.
What if your sky is more lit up, and you can’t find the Andromeda galaxy with the eyes alone? Some stargazers use binoculars and star-hop to the Andromeda galaxy via this W-shaped constellation.
Cassiopeia appears in the northeast sky at nightfall and early evening, then swings upward as evening deepens into late night. In the wee hours before dawn, Cassiopeia is found high over Polaris, the North Star. Note that one-half of the W is more deeply notched than the other half. This deeper V is your “arrow” in the sky, pointing to the Andromeda galaxy.
The Andromeda galaxy is the nearest large spiral galaxy to our Milky Way. It’s about 2.5 million light-years away, teeming with hundreds of billions of stars.
View larger. | Josh Blash shot this in 2014. He wrote, “M31, the Andromeda Galaxy. I used 29 frames shot at 90mm and tracked for 60 seconds each, then stacked them using the DeepSkyStacker software.” See more photos by Josh Blash on Facebook.
Draw an imaginary line from the star Kappa Cassiopeiae (abbreviated Kappa) through the star Schedar, then go about 3 times the Kappa-Schedar distance to locate the Andromeda galaxy (Messier 31).
Bottom line: You can find the Andromeda galaxy using the constellation Cassiopeia as a guide. Remember, on a dark night, this galaxy looks like a faint smudge of light. Once you’ve found it with the unaided eye or binoculars, try with a telescope if you have one.
Tonight, if you have a dark sky, try star-hopping to the Andromeda galaxy from the constellation Cassiopeia the Queen. If your sky is truly dark, you might even spot this hazy patch of light with no optical aid, as the ancient stargazers did before the days of light pollution.
What if your sky is more lit up, and you can’t find the Andromeda galaxy with the eyes alone? Some stargazers use binoculars and star-hop to the Andromeda galaxy via this W-shaped constellation.
Cassiopeia appears in the northeast sky at nightfall and early evening, then swings upward as evening deepens into late night. In the wee hours before dawn, Cassiopeia is found high over Polaris, the North Star. Note that one-half of the W is more deeply notched than the other half. This deeper V is your “arrow” in the sky, pointing to the Andromeda galaxy.
The Andromeda galaxy is the nearest large spiral galaxy to our Milky Way. It’s about 2.5 million light-years away, teeming with hundreds of billions of stars.
View larger. | Josh Blash shot this in 2014. He wrote, “M31, the Andromeda Galaxy. I used 29 frames shot at 90mm and tracked for 60 seconds each, then stacked them using the DeepSkyStacker software.” See more photos by Josh Blash on Facebook.
Draw an imaginary line from the star Kappa Cassiopeiae (abbreviated Kappa) through the star Schedar, then go about 3 times the Kappa-Schedar distance to locate the Andromeda galaxy (Messier 31).
Bottom line: You can find the Andromeda galaxy using the constellation Cassiopeia as a guide. Remember, on a dark night, this galaxy looks like a faint smudge of light. Once you’ve found it with the unaided eye or binoculars, try with a telescope if you have one.
This 3-paneled artist’s concept illustrates new research, explaining why the bright red supergiant star Betelgeuse suddenly became fainter for several months during late 2019 and early 2020. In panel 1, a bright, hot blob of plasma is ejected from the star. In panel 2, outflowing expelled gas rapidly expands outward and cools to form an enormous cloud of obscuring dust. In panel 3, the huge dust cloud partially blocks Betelgeuse’s light. Image via NASA/ ESA/ E. Wheatley (STScI)/ CfA.
For us skywatchers, it was lots of fun – and entirely shocking – when the well-known bright star Betelgeuse unexpectedly dimmed in late 2019 and early 2020. Betelgeuse has been such a steadfast sight in the night sky throughout our lives (and some of us have been around awhile), shining with a red light at the shoulder of the easy-to-see constellation Orion the Hunter. The dimming of Betelgeuse was even more exciting because it’s a well-known fact that this star will someday explode. Was the sudden dimming of Betelgeuse a sign that it would explode soon? Speculation raged for weeks, as we gazed toward a fainter Betelgeuse than we’d ever seen before. The star did not explode. In fact, by February, it was starting to brighten again. Then last week – on August 13, 2020 – scientists released a new study suggesting that the sudden dimming of Betelgeuse was most likely caused by the ejection and cooling of dense hot gases. In the meantime, as I write this, it appears Betelgeuse is dimming once more, about a year earlier than expected.
A statement from the Harvard & Smithsonian Center for Astrophysics (CfA) explained:
Between October and November 2019, Hubble Space Telescope observed dense, heated material moving outward through the star’s extended atmosphere at 200,000 miles per hour. The following month, several ground-based telescopes observed a decrease in brightness in Betelgeuse’s southern hemisphere, as if something was blocking light in this region of the star. By February 2020, the star had lost more than two-thirds of its brilliance, a dimming visible even to the unaided eye, creating buzz that the star might be going supernova. Continued ultraviolet light spectroscopic observations with Hubble provided a timeline for researchers to follow, like breadcrumbs leading back through time to pinpoint the source of the mysterious dimming.
Andrea Dupree is associate director of the Harvard & Smithsonian Center for Astrophysics and lead author of the study, which was published on August 13 in the peer-reviewedThe Astrophysical Journal. She said in the scientists’ statement:
With Hubble, we had previously observed hot convection cells on the surface of Betelgeuse and in the fall of 2019 we discovered a large amount of dense hot gas moving outwards through Betelgeuse’s extended atmosphere. We think this gas cooled down millions of miles outside the star to form the dust that blocked the southern part of the star imaged in January and February.
The material was two to four times more luminous than the star’s normal brightness. And then, about a month later the south part of Betelgeuse dimmed conspicuously as the star grew fainter. We think it possible that a dark cloud resulted from the outflow that Hubble detected. Only Hubble gives us this evidence that led up to the dimming.
This spectral plot is based on Hubble Space Telescope observations from March 2019 to February 2020. Hubble recorded a surprising outburst in the atmosphere of the nearby red supergiant star Betelgeuse. Measurements of emission from magnesium II were used to trace motion in the star’s pulsating atmosphere. Hubble’s Space Telescope Imaging Spectrograph captured a dramatic increase in the brightness of magnesium emission in October 2019, in the southeast region of the star, as outlined by the white circle. (Betelgeuse is close enough and big enough for Hubble to resolve the star’s enormous disk.) This traumatic event was different from what is normally seen in the star’s 420-day pulsation period. At the same time in October, the star abruptly began dimming. This fading continued until February 2020, at which time the Hubble ultraviolet spectral data had returned to normal. The outburst is suspected to have ejected a cloud of hot plasma that cooled to form dust that blocked out a significant portion of the star’s light for a few months. Hubble’s long baseline of monitoring the star helped put the puzzle pieces together. Image via NASA/ ESA/ A. Dupree (CfA)/ E. Wheatley (STScI)/ CfA.
Scientists’ models had suggested that – in this situation – the plasma should be ejected from the star’s rotational poles. The Hubble observations showed it was not, however. Dupree said:
Hubble observations suggest that material can be driven off from any part of the stellar surface.
Dupree added that recent activity on Betelgeuse was not normal for this star. Dupree noted that Betelgeuse is losing mass at a rate 30 million times higher than the sun, but that recent activity resulted in a loss of roughly two times the normal amount of material from the star’s southern hemisphere alone. She said:
All stars are losing material to the interstellar medium, and we don’t know how this material is lost. Is it a smooth wind blowing all the time? Or does it come in fits and starts? Perhaps with an event such as we discovered on Betelgeuse? We know that other hotter, luminous stars lose material and it quickly turns to dust making the star appear much fainter.
But, in over a century and a half, this has not happened to Betelgeuse. It’s very unique.
An image from NASA’s STEREO spacecraft shows the star Betelgeuse, circled. For several weeks in 2020, STEREO was the only observatory making measurements of Betelgeuse because of the spacecraft’s unique position in space. Between late June and early August 2020, STEREO observed Betelgeuse on five separate days, measuring the star’s relative brightness in comparison to other stars. Image via NASA/ STEREO.
The star Betelgeuse, and its constellation Orion, are behind the sun as seen from Earth in early Northern Hemisphere summer. They always return to our early morning sky around late July and early August. While Betelgeuse was hidden behind the sun for earthly observers, scientists turned to NASA’s Solar TErrestrial RElations Observatory – STEREO – to monitor the star’s brightness. Those observations revealed another surprise, the scientists said: more unexpected dimming.
Between late June and early August 2020, STEREO observed Betelgeuse on five separate days, measuring the star’s relative brightness in comparison to other stars. Dupree said:
Our observations of Betelgeuse with STEREO confirm that the star is dimming again.
Betelgeuse is a variable star, though its rising and falling in brightness isn’t noticeable to casual observers. It typically goes through brightness cycles lasting around 420 days.
Since the previous minimum happened in February 2020, this new dimming is over a year early, the scientists commented.
Dupree said she plans to observe Betelgeuse with STEREO again next year, during the star’s maximum, to monitor for unexpected outbursts.
People always want to know if Betelgeuse will explode. It is an old star and a supergiant star, and so the answer to that question is surely yes. When Betelgeuse dimmed so noticeably in late 2019 and early 2020, some scientists agreed it might be a sign that the star was about to go supernova. These scientists commented in their statement:
Betelgeuse is a bright star in our galaxy, near the end of its life, that is likely to become a supernova. When the star became very faint in February 2020, this was the faintest that it had ever been since measurements began over 150 years ago. The dimming was obvious to everyone when looking at the constellation Orion; it was very weird, Betelgeuse was almost missing.
At 725 light-years away, light – and dimming – seen from Betelgeuse today on Earth left the star in the year 1300. Dupree said:
No one knows how a star behaves in the weeks before it explodes, and there were some ominous predictions that Betelgeuse was ready to become a supernova.
Chances are, however, that it will not explode during our lifetime, but who knows?
Bottom line: An explanation for the mysterious dimming of Betelgeuse in late 2019 and early 2020.
This 3-paneled artist’s concept illustrates new research, explaining why the bright red supergiant star Betelgeuse suddenly became fainter for several months during late 2019 and early 2020. In panel 1, a bright, hot blob of plasma is ejected from the star. In panel 2, outflowing expelled gas rapidly expands outward and cools to form an enormous cloud of obscuring dust. In panel 3, the huge dust cloud partially blocks Betelgeuse’s light. Image via NASA/ ESA/ E. Wheatley (STScI)/ CfA.
For us skywatchers, it was lots of fun – and entirely shocking – when the well-known bright star Betelgeuse unexpectedly dimmed in late 2019 and early 2020. Betelgeuse has been such a steadfast sight in the night sky throughout our lives (and some of us have been around awhile), shining with a red light at the shoulder of the easy-to-see constellation Orion the Hunter. The dimming of Betelgeuse was even more exciting because it’s a well-known fact that this star will someday explode. Was the sudden dimming of Betelgeuse a sign that it would explode soon? Speculation raged for weeks, as we gazed toward a fainter Betelgeuse than we’d ever seen before. The star did not explode. In fact, by February, it was starting to brighten again. Then last week – on August 13, 2020 – scientists released a new study suggesting that the sudden dimming of Betelgeuse was most likely caused by the ejection and cooling of dense hot gases. In the meantime, as I write this, it appears Betelgeuse is dimming once more, about a year earlier than expected.
A statement from the Harvard & Smithsonian Center for Astrophysics (CfA) explained:
Between October and November 2019, Hubble Space Telescope observed dense, heated material moving outward through the star’s extended atmosphere at 200,000 miles per hour. The following month, several ground-based telescopes observed a decrease in brightness in Betelgeuse’s southern hemisphere, as if something was blocking light in this region of the star. By February 2020, the star had lost more than two-thirds of its brilliance, a dimming visible even to the unaided eye, creating buzz that the star might be going supernova. Continued ultraviolet light spectroscopic observations with Hubble provided a timeline for researchers to follow, like breadcrumbs leading back through time to pinpoint the source of the mysterious dimming.
Andrea Dupree is associate director of the Harvard & Smithsonian Center for Astrophysics and lead author of the study, which was published on August 13 in the peer-reviewedThe Astrophysical Journal. She said in the scientists’ statement:
With Hubble, we had previously observed hot convection cells on the surface of Betelgeuse and in the fall of 2019 we discovered a large amount of dense hot gas moving outwards through Betelgeuse’s extended atmosphere. We think this gas cooled down millions of miles outside the star to form the dust that blocked the southern part of the star imaged in January and February.
The material was two to four times more luminous than the star’s normal brightness. And then, about a month later the south part of Betelgeuse dimmed conspicuously as the star grew fainter. We think it possible that a dark cloud resulted from the outflow that Hubble detected. Only Hubble gives us this evidence that led up to the dimming.
This spectral plot is based on Hubble Space Telescope observations from March 2019 to February 2020. Hubble recorded a surprising outburst in the atmosphere of the nearby red supergiant star Betelgeuse. Measurements of emission from magnesium II were used to trace motion in the star’s pulsating atmosphere. Hubble’s Space Telescope Imaging Spectrograph captured a dramatic increase in the brightness of magnesium emission in October 2019, in the southeast region of the star, as outlined by the white circle. (Betelgeuse is close enough and big enough for Hubble to resolve the star’s enormous disk.) This traumatic event was different from what is normally seen in the star’s 420-day pulsation period. At the same time in October, the star abruptly began dimming. This fading continued until February 2020, at which time the Hubble ultraviolet spectral data had returned to normal. The outburst is suspected to have ejected a cloud of hot plasma that cooled to form dust that blocked out a significant portion of the star’s light for a few months. Hubble’s long baseline of monitoring the star helped put the puzzle pieces together. Image via NASA/ ESA/ A. Dupree (CfA)/ E. Wheatley (STScI)/ CfA.
Scientists’ models had suggested that – in this situation – the plasma should be ejected from the star’s rotational poles. The Hubble observations showed it was not, however. Dupree said:
Hubble observations suggest that material can be driven off from any part of the stellar surface.
Dupree added that recent activity on Betelgeuse was not normal for this star. Dupree noted that Betelgeuse is losing mass at a rate 30 million times higher than the sun, but that recent activity resulted in a loss of roughly two times the normal amount of material from the star’s southern hemisphere alone. She said:
All stars are losing material to the interstellar medium, and we don’t know how this material is lost. Is it a smooth wind blowing all the time? Or does it come in fits and starts? Perhaps with an event such as we discovered on Betelgeuse? We know that other hotter, luminous stars lose material and it quickly turns to dust making the star appear much fainter.
But, in over a century and a half, this has not happened to Betelgeuse. It’s very unique.
An image from NASA’s STEREO spacecraft shows the star Betelgeuse, circled. For several weeks in 2020, STEREO was the only observatory making measurements of Betelgeuse because of the spacecraft’s unique position in space. Between late June and early August 2020, STEREO observed Betelgeuse on five separate days, measuring the star’s relative brightness in comparison to other stars. Image via NASA/ STEREO.
The star Betelgeuse, and its constellation Orion, are behind the sun as seen from Earth in early Northern Hemisphere summer. They always return to our early morning sky around late July and early August. While Betelgeuse was hidden behind the sun for earthly observers, scientists turned to NASA’s Solar TErrestrial RElations Observatory – STEREO – to monitor the star’s brightness. Those observations revealed another surprise, the scientists said: more unexpected dimming.
Between late June and early August 2020, STEREO observed Betelgeuse on five separate days, measuring the star’s relative brightness in comparison to other stars. Dupree said:
Our observations of Betelgeuse with STEREO confirm that the star is dimming again.
Betelgeuse is a variable star, though its rising and falling in brightness isn’t noticeable to casual observers. It typically goes through brightness cycles lasting around 420 days.
Since the previous minimum happened in February 2020, this new dimming is over a year early, the scientists commented.
Dupree said she plans to observe Betelgeuse with STEREO again next year, during the star’s maximum, to monitor for unexpected outbursts.
People always want to know if Betelgeuse will explode. It is an old star and a supergiant star, and so the answer to that question is surely yes. When Betelgeuse dimmed so noticeably in late 2019 and early 2020, some scientists agreed it might be a sign that the star was about to go supernova. These scientists commented in their statement:
Betelgeuse is a bright star in our galaxy, near the end of its life, that is likely to become a supernova. When the star became very faint in February 2020, this was the faintest that it had ever been since measurements began over 150 years ago. The dimming was obvious to everyone when looking at the constellation Orion; it was very weird, Betelgeuse was almost missing.
At 725 light-years away, light – and dimming – seen from Betelgeuse today on Earth left the star in the year 1300. Dupree said:
No one knows how a star behaves in the weeks before it explodes, and there were some ominous predictions that Betelgeuse was ready to become a supernova.
Chances are, however, that it will not explode during our lifetime, but who knows?
Bottom line: An explanation for the mysterious dimming of Betelgeuse in late 2019 and early 2020.
NASA’s newest planet-hunting space telescope – the Transiting Exoplanet Survey Satellite, aka TESS – has just completed its primary mission, the space agency announced on August 11, 2020. Its initial survey of the sky took two years. In this time, TESS helped revolutionize our knowledge about exoplanets, worlds orbiting distant stars, continuing on from where the Kepler space telescope, NASA’s first planet-hunter, left off.
TESS’ primary mission officially finished on July 4, 2020. After this, TESS will continue with its extended mission phase.
During the two-year survey, TESS images about 75 percent of the sky, and so far has found 66 new confirmed exoplanets and nearly 2,100 additional candidates that are awaiting confirmation. Patricia Boyd, project scientist for TESS at NASA’s Goddard Space Flight Center, said in a statement:
TESS is producing a torrent of high-quality observations providing valuable data across a wide range of science topics.
During the first year, TESS observed 13 different sectors of the sky seen from the southern hemisphere, and then turned its attention to the northern sky in the second year. Each sector is a 24-by-96-degree strip of the sky, and TESS spends about a month surveying each sector.
View of the Southern Hemisphere sky from TESS. You can see the glowing band of our Milky Way galaxy (left), the Orion Nebula (top), and the Large Magellanic Cloud (center). The dark lines are gaps between the detectors in TESS’s camera system. Image via NASA/ MIT/ TESS/ Ethan Kruse (USRA).
Now, TESS has returned to watching the northern sky again as it enters its extended mission. With that shift comes some other changes and improvements as well, according to NASA.
TESS is now collecting data faster and more efficiently than it did during the primary mission, NASA said. The telescope’s cameras can now capture a full image every 10 minutes, three times faster than they did in the primary mission. Also, by using a new fast mode, TESS can measure the brightness of thousands of stars every 20 seconds. Previously, the telescope would make similar measurements every two minutes. These improvements are not just good for planet-hunting, they also help TESS better resolve brightness changes caused by stellar oscillations and observe explosive flares from active stars in greater detail.
This extended mission phase will continue until September 2022. TESS will spend the next year observing the southern sky, then will once again go back to surveying the northern sky for a period of 15 months. Those surveys will include observations along the ecliptic – the plane of Earth’s orbit around the sun – that TESS has not yet imaged.
How does TESS find exoplanets?
Like many other telescopes, TESS uses the transit method of detecting exoplanets. That is, its instruments are geared to detecting slight decreases in the brightnesses of stars as planets pass in front of those stars, as seen from Earth. Those temporary dips in brightness are very tiny, but TESS is able to see them, and determine whether they are caused by a planet (in most cases, NASA said, they are).
Last January, NASA announced that TESS had discovered its first Earth-sized planet in the habitable zone of its red dwarf star, TOI 700 d. The habitable zone is the region around a star where temperatures on a rocky planet could allow liquid water to exist. The planet was later confirmed by NASA’s Spitzer Space Telescope. This planetary system is just over 100 light-years away in the constellation Dorado. According to Paul Hertz, astrophysics division director at NASA Headquarters in Washington:
TESS was designed and launched specifically to find Earth-sized planets orbiting nearby stars. Planets around nearby stars are easiest to follow-up with larger telescopes in space and on Earth. Discovering TOI 700 d is a key science finding for TESS. Confirming the planet’s size and habitable zone status with Spitzer is another win for Spitzer as it approaches the end of science operations this January.
Artist’s concept of TOI 700 d, the first Earth-sized exoplanet that TESS found in the habitable zone of its star. This planetary system is 100 light-years away in the constellation Dorado. Image via Goddard Space Flight Center/ Wikipedia.
TOI 700 d is the outermost of three known planets in the system and the only one in the habitable zone. It measures 20% larger than Earth, orbits its red dwarf star every 37 days and receives from its star 86% of the energy that the sun provides to Earth.
It is expected that TESS will find many more Earth-sized worlds, including ones that are potentially habitable.
In June, scientists reported that TESS found a Neptune-sized planet, AU Mic b, orbiting a very young red dwarf star. Bryson Cale, a doctoral student at George Mason University, said:
AU Mic is a young, nearby M dwarf star. It’s surrounded by a vast debris disk in which moving clumps of dust have been tracked, and now, thanks to TESS and Spitzer, it has a planet with a direct size measurement. There is no other known system that checks all of these important boxes.
The star is only 10 – 20 million years old, and the planet completes an orbit in only 8.5 days.
TESS also recently found its first circumbinary planet – one that orbits two stars – called TOI 1338 b. The two stars orbit each other every 15 days. One is about 10% more massive than our sun, while the other is cooler, dimmer and only one-third the sun’s mass. The planet is about 6.9 times the size of Earth, between the size of Neptune and Saturn.
TESS even caught a black hole in a distant galaxy in the act of tearing apart a sun-like star with its enormous gravity! Thomas Holoien, of the Carnegie Observatories is lead author of a paper that described the findings on September 27, 2019 in The Astrophysical Journal. Holoien said:
TESS data let us see exactly when this destructive event, named ASASSN-19bt, started to get brighter, which we’ve never been able to do before. Because we identified the tidal disruption quickly with the ground-based All-Sky Automated Survey for Supernovae (ASAS-SN), we were able to trigger multiwavelength follow-up observations in the first few days. The early data will be incredibly helpful for modeling the physics of these outbursts.
Last November, it was also announced that TESS would be teaming up with Breakthrough Listen (part of Breakthrough Initiatives) in the search for extraterrestrial intelligence, aka SETI. Basically, TESS will identify objects of interest, such as potentially habitable exoplanets, for other telescopes to point at and search for radio signals or other signs of advanced technologies, called technosignatures.
In only the first couple years of its mission, TESS has not only found thousands of new exoplanets, but has observed and witnessed a wide variety of incredible cosmic objects and phenomena. What else will it find in the years ahead?
Artist’s illustration of TESS. The planet-hunting space telescope has now completed its primary mission and is now moving into its extended mission. It has already found nearly 2,100 exoplanet candidates and 66 confirmed new worlds. Image via NASA/ Goddard Space Flight Center.
Bottom line: NASA’s planet-hunting space telescope TESS has completed its primary mission.
NASA’s newest planet-hunting space telescope – the Transiting Exoplanet Survey Satellite, aka TESS – has just completed its primary mission, the space agency announced on August 11, 2020. Its initial survey of the sky took two years. In this time, TESS helped revolutionize our knowledge about exoplanets, worlds orbiting distant stars, continuing on from where the Kepler space telescope, NASA’s first planet-hunter, left off.
TESS’ primary mission officially finished on July 4, 2020. After this, TESS will continue with its extended mission phase.
During the two-year survey, TESS images about 75 percent of the sky, and so far has found 66 new confirmed exoplanets and nearly 2,100 additional candidates that are awaiting confirmation. Patricia Boyd, project scientist for TESS at NASA’s Goddard Space Flight Center, said in a statement:
TESS is producing a torrent of high-quality observations providing valuable data across a wide range of science topics.
During the first year, TESS observed 13 different sectors of the sky seen from the southern hemisphere, and then turned its attention to the northern sky in the second year. Each sector is a 24-by-96-degree strip of the sky, and TESS spends about a month surveying each sector.
View of the Southern Hemisphere sky from TESS. You can see the glowing band of our Milky Way galaxy (left), the Orion Nebula (top), and the Large Magellanic Cloud (center). The dark lines are gaps between the detectors in TESS’s camera system. Image via NASA/ MIT/ TESS/ Ethan Kruse (USRA).
Now, TESS has returned to watching the northern sky again as it enters its extended mission. With that shift comes some other changes and improvements as well, according to NASA.
TESS is now collecting data faster and more efficiently than it did during the primary mission, NASA said. The telescope’s cameras can now capture a full image every 10 minutes, three times faster than they did in the primary mission. Also, by using a new fast mode, TESS can measure the brightness of thousands of stars every 20 seconds. Previously, the telescope would make similar measurements every two minutes. These improvements are not just good for planet-hunting, they also help TESS better resolve brightness changes caused by stellar oscillations and observe explosive flares from active stars in greater detail.
This extended mission phase will continue until September 2022. TESS will spend the next year observing the southern sky, then will once again go back to surveying the northern sky for a period of 15 months. Those surveys will include observations along the ecliptic – the plane of Earth’s orbit around the sun – that TESS has not yet imaged.
How does TESS find exoplanets?
Like many other telescopes, TESS uses the transit method of detecting exoplanets. That is, its instruments are geared to detecting slight decreases in the brightnesses of stars as planets pass in front of those stars, as seen from Earth. Those temporary dips in brightness are very tiny, but TESS is able to see them, and determine whether they are caused by a planet (in most cases, NASA said, they are).
Last January, NASA announced that TESS had discovered its first Earth-sized planet in the habitable zone of its red dwarf star, TOI 700 d. The habitable zone is the region around a star where temperatures on a rocky planet could allow liquid water to exist. The planet was later confirmed by NASA’s Spitzer Space Telescope. This planetary system is just over 100 light-years away in the constellation Dorado. According to Paul Hertz, astrophysics division director at NASA Headquarters in Washington:
TESS was designed and launched specifically to find Earth-sized planets orbiting nearby stars. Planets around nearby stars are easiest to follow-up with larger telescopes in space and on Earth. Discovering TOI 700 d is a key science finding for TESS. Confirming the planet’s size and habitable zone status with Spitzer is another win for Spitzer as it approaches the end of science operations this January.
Artist’s concept of TOI 700 d, the first Earth-sized exoplanet that TESS found in the habitable zone of its star. This planetary system is 100 light-years away in the constellation Dorado. Image via Goddard Space Flight Center/ Wikipedia.
TOI 700 d is the outermost of three known planets in the system and the only one in the habitable zone. It measures 20% larger than Earth, orbits its red dwarf star every 37 days and receives from its star 86% of the energy that the sun provides to Earth.
It is expected that TESS will find many more Earth-sized worlds, including ones that are potentially habitable.
In June, scientists reported that TESS found a Neptune-sized planet, AU Mic b, orbiting a very young red dwarf star. Bryson Cale, a doctoral student at George Mason University, said:
AU Mic is a young, nearby M dwarf star. It’s surrounded by a vast debris disk in which moving clumps of dust have been tracked, and now, thanks to TESS and Spitzer, it has a planet with a direct size measurement. There is no other known system that checks all of these important boxes.
The star is only 10 – 20 million years old, and the planet completes an orbit in only 8.5 days.
TESS also recently found its first circumbinary planet – one that orbits two stars – called TOI 1338 b. The two stars orbit each other every 15 days. One is about 10% more massive than our sun, while the other is cooler, dimmer and only one-third the sun’s mass. The planet is about 6.9 times the size of Earth, between the size of Neptune and Saturn.
TESS even caught a black hole in a distant galaxy in the act of tearing apart a sun-like star with its enormous gravity! Thomas Holoien, of the Carnegie Observatories is lead author of a paper that described the findings on September 27, 2019 in The Astrophysical Journal. Holoien said:
TESS data let us see exactly when this destructive event, named ASASSN-19bt, started to get brighter, which we’ve never been able to do before. Because we identified the tidal disruption quickly with the ground-based All-Sky Automated Survey for Supernovae (ASAS-SN), we were able to trigger multiwavelength follow-up observations in the first few days. The early data will be incredibly helpful for modeling the physics of these outbursts.
Last November, it was also announced that TESS would be teaming up with Breakthrough Listen (part of Breakthrough Initiatives) in the search for extraterrestrial intelligence, aka SETI. Basically, TESS will identify objects of interest, such as potentially habitable exoplanets, for other telescopes to point at and search for radio signals or other signs of advanced technologies, called technosignatures.
In only the first couple years of its mission, TESS has not only found thousands of new exoplanets, but has observed and witnessed a wide variety of incredible cosmic objects and phenomena. What else will it find in the years ahead?
Artist’s illustration of TESS. The planet-hunting space telescope has now completed its primary mission and is now moving into its extended mission. It has already found nearly 2,100 exoplanet candidates and 66 confirmed new worlds. Image via NASA/ Goddard Space Flight Center.
Bottom line: NASA’s planet-hunting space telescope TESS has completed its primary mission.
If you’re outside on an August or September evening, you can glimpse the zodiacal constellation Sagittarius the Archer. From our northerly latitudes, it never climbs high in the sky. Yet Sagittarius marks the direction in our sky to one of the most wondrous places we can imagine: the center of our own Milky Way galaxy. And the constellation is fairly easy to spot, because its brightest stars form a distinctive shape of a Teapot. Follow the links below to learn how to see Sagittarius, and about the lore and science of this constellation.
The Teapot asterism in the constellation Sagittarius. This image is from Eileen Claffey. She captured it in mid-September 2012. At that time of year, Sagittarius is headed toward the sunset glare.
How to see the constellation Sagittarius. If you want to see Sagittarius, you’ll want first to find a dark location.
In August or September, if you go someplace really dark, and simply look up in the evening, you’ll see the starlit band of the Milky Way. It’ll appear as a hazy band stretching all the way across the sky. The haze is really countless stars. From the Northern Hemisphere, the starlit trail of the Milky Way seems to bulge just before it reaches the southern horizon. You can see this bulge in the night sky, and it marks the approximate location of the Milky Way’s center, which is located within the boundaries of the constellation Sagittarius.
Here’s another way to find Sagittarius. If you’re familiar with the Summer Triangle asterism, draw an imaginary line from the star Deneb and through the star Altair to locate Sagittarius near the horizon. At mid-northern latitudes, the Summer Triangle hangs high in the south to overhead on late summer and autumn evenings.
See the Teapot of Sagittarius in this photo? The center of the galaxy is located in this direction. Image via Lewistown StormWatcher.
What’s the difference between the constellation Sagittarius and the sign? In our modern times, the sun passes in front of the constellation Sagittarius from about December 18 to January 20. These dates are off by about a month from what you read on the horoscope page. The sun moves through the sign Sagittarius from about November 21 to December 21.
Yes, there is a difference between an astronomical constellation and an astrological sign! Keep in mind that we’re talking about the constellation Sagittarius in this article. The horoscope is referring to the sign Sagittarius.
By definition, the sun enters the sign Sagittarius whenever the sun is precisely 30o west of the December solstice point. Then, on the December solstice, the sun enters the sign Capricorn.
While the signs remain fixed relative to the solstices and equinoxes, the solstices and equinox points move 30o westward in front of the constellations – or backdrop stars – in about 2,160 years.
The constellation boundaries were formally defined by the International Astronomical Union (IAU) in 1930. Based on the present IAU boundaries, the December solstice point moved into the constellation Sagittarius in the year -130 (131 B.C.) and will move into the constellation Ophiuchus in 2269 (A.D. 2269).
Deep-sky wonders in Sagittarius. Sagittarius points to the heart of the Milky Way galaxy. We can’t see all the way to the galactic center because the plethora of stars, star clusters and nebulae between us and the Milky Way center veil it from view.
But trying viewing these deep-sky treasures in Sagittarius with binoculars or the telescope: Sagittarius Star Cloud (Messier 24), globular cluster Messier 22, Lagoon Nebula (Messier 8), Trifid Nebula (Messier 20) and Omega Nebula (Messier 17). Sharp-eyed people can even see these deep-sky objects with the unaided eye. (The above sky chart locates these sites for you.)
Modern stargazers have difficulty making out the Centaur that this constellation is supposed to depict. Most people have an easier time seeing the Teapot asterism in the western half of Sagittarius. Once you learn the Teapot, it’ll greatly assist you on your star-hopping adventures to deep-sky marvels.
Sagittarius in mythology, and more. The constellations Sagittarius and Centaurus are both supposed to represent a centaur – a creature with the upper torso of a man and the hindquarters of a horse. Historically, centaurs might have really been cowboys, using horses to round up cattle in ancient Greece.
According to Greek myth, the centaurs were the offspring of Ixion and the cloud nymph Nephele. Apparently, Sagittarius’ drawn-out bow and arrow originated from the Mesopotamian archer god, and this constellation might not have always represented the centaur Chiron.
It’s said that the Greeks associated Sagittarius with Crotus the satyr – another type of part man, part horse and part goat monstrosity. Quite possibly, the Romans first identified the constellation Sagittarius with Chiron, the wise and kindly centaur.
Here’s soemthing that distinguishes Sagittarius the Archer from the other 13 constellations of the zodiac. The sun shines in front of this constellation on the December 21 solstice.
Also, the ecliptic – the sun’s yearly pathway in front of the backdrop stars – intersects the galactic equator in Sagittarius. Although the sun crosses the galactic equator twice a year every year, much ado was made about the alignment of the December solstice sun with the galactic equator in 2012. Actually, if we are to accept the galactic coordinates as defined by the International Astronomical Union in 1959, the solstice points were in alignment with the galactic equator in 1998. By 2012, the time had long passed.
If you spot Sagittarius, don’t forget to look nearby for neighboring Scorpius. Image via Matthew Chin in Hong Kong.
Bottom line: Look for the constellation Sagittarius on an August or September evening. The brightest stars in Sagittarius form a distinctive shape of a teapot.
If you’re outside on an August or September evening, you can glimpse the zodiacal constellation Sagittarius the Archer. From our northerly latitudes, it never climbs high in the sky. Yet Sagittarius marks the direction in our sky to one of the most wondrous places we can imagine: the center of our own Milky Way galaxy. And the constellation is fairly easy to spot, because its brightest stars form a distinctive shape of a Teapot. Follow the links below to learn how to see Sagittarius, and about the lore and science of this constellation.
The Teapot asterism in the constellation Sagittarius. This image is from Eileen Claffey. She captured it in mid-September 2012. At that time of year, Sagittarius is headed toward the sunset glare.
How to see the constellation Sagittarius. If you want to see Sagittarius, you’ll want first to find a dark location.
In August or September, if you go someplace really dark, and simply look up in the evening, you’ll see the starlit band of the Milky Way. It’ll appear as a hazy band stretching all the way across the sky. The haze is really countless stars. From the Northern Hemisphere, the starlit trail of the Milky Way seems to bulge just before it reaches the southern horizon. You can see this bulge in the night sky, and it marks the approximate location of the Milky Way’s center, which is located within the boundaries of the constellation Sagittarius.
Here’s another way to find Sagittarius. If you’re familiar with the Summer Triangle asterism, draw an imaginary line from the star Deneb and through the star Altair to locate Sagittarius near the horizon. At mid-northern latitudes, the Summer Triangle hangs high in the south to overhead on late summer and autumn evenings.
See the Teapot of Sagittarius in this photo? The center of the galaxy is located in this direction. Image via Lewistown StormWatcher.
What’s the difference between the constellation Sagittarius and the sign? In our modern times, the sun passes in front of the constellation Sagittarius from about December 18 to January 20. These dates are off by about a month from what you read on the horoscope page. The sun moves through the sign Sagittarius from about November 21 to December 21.
Yes, there is a difference between an astronomical constellation and an astrological sign! Keep in mind that we’re talking about the constellation Sagittarius in this article. The horoscope is referring to the sign Sagittarius.
By definition, the sun enters the sign Sagittarius whenever the sun is precisely 30o west of the December solstice point. Then, on the December solstice, the sun enters the sign Capricorn.
While the signs remain fixed relative to the solstices and equinoxes, the solstices and equinox points move 30o westward in front of the constellations – or backdrop stars – in about 2,160 years.
The constellation boundaries were formally defined by the International Astronomical Union (IAU) in 1930. Based on the present IAU boundaries, the December solstice point moved into the constellation Sagittarius in the year -130 (131 B.C.) and will move into the constellation Ophiuchus in 2269 (A.D. 2269).
Deep-sky wonders in Sagittarius. Sagittarius points to the heart of the Milky Way galaxy. We can’t see all the way to the galactic center because the plethora of stars, star clusters and nebulae between us and the Milky Way center veil it from view.
But trying viewing these deep-sky treasures in Sagittarius with binoculars or the telescope: Sagittarius Star Cloud (Messier 24), globular cluster Messier 22, Lagoon Nebula (Messier 8), Trifid Nebula (Messier 20) and Omega Nebula (Messier 17). Sharp-eyed people can even see these deep-sky objects with the unaided eye. (The above sky chart locates these sites for you.)
Modern stargazers have difficulty making out the Centaur that this constellation is supposed to depict. Most people have an easier time seeing the Teapot asterism in the western half of Sagittarius. Once you learn the Teapot, it’ll greatly assist you on your star-hopping adventures to deep-sky marvels.
Sagittarius in mythology, and more. The constellations Sagittarius and Centaurus are both supposed to represent a centaur – a creature with the upper torso of a man and the hindquarters of a horse. Historically, centaurs might have really been cowboys, using horses to round up cattle in ancient Greece.
According to Greek myth, the centaurs were the offspring of Ixion and the cloud nymph Nephele. Apparently, Sagittarius’ drawn-out bow and arrow originated from the Mesopotamian archer god, and this constellation might not have always represented the centaur Chiron.
It’s said that the Greeks associated Sagittarius with Crotus the satyr – another type of part man, part horse and part goat monstrosity. Quite possibly, the Romans first identified the constellation Sagittarius with Chiron, the wise and kindly centaur.
Here’s soemthing that distinguishes Sagittarius the Archer from the other 13 constellations of the zodiac. The sun shines in front of this constellation on the December 21 solstice.
Also, the ecliptic – the sun’s yearly pathway in front of the backdrop stars – intersects the galactic equator in Sagittarius. Although the sun crosses the galactic equator twice a year every year, much ado was made about the alignment of the December solstice sun with the galactic equator in 2012. Actually, if we are to accept the galactic coordinates as defined by the International Astronomical Union in 1959, the solstice points were in alignment with the galactic equator in 1998. By 2012, the time had long passed.
If you spot Sagittarius, don’t forget to look nearby for neighboring Scorpius. Image via Matthew Chin in Hong Kong.
Bottom line: Look for the constellation Sagittarius on an August or September evening. The brightest stars in Sagittarius form a distinctive shape of a teapot.
We’ve recently seen Orion’s return to the east before dawn, which means our northern summer is beginning to draw to a close. But the Summer Triangle asterism still rules the skies. It pops out first thing at nightfall and climbs highest up for the night at late evening. From mid-northern latitudes, Vega – the Summer Triangle’s brightest star – shines high overhead around 10 p.m. local daylight saving time (9 p.m. local standard time). Altair resides to the southeast (lower left) of Vega, and Deneb lies to Vega’s east (left).
The Summer Triangle is not a constellation. It is three bright stars in three different constellations, as the wonderful photo below – by Susan Jensen in Odessa, Washington – shows.
Here is the Summer Triangle asterism – 3 bright stars in 3 different constellations – as photographed by Susan Jensen in Odessa, Washington.
As the stars drift westward during the night, Deneb will swing upward to replace Vega as the overhead star some two hours later. Of course, the stars aren’t really moving. It’s the Earth’s rotation that causes the stars to move westward during the night, and the sun to go westward during the day.
Great rift of Milky Way passes through the constellation Cassiopeia and the Summer Triangle. Click here for a larger photo
Because the three stars making up the Summer Triangle are 1st-magnitude stars, you can easily see the brilliant Summer Triangle on moonlit nights. However, you need a dark sky free of moonlight to see the great swath of stars known as the Milky Way passing in between the Summer Triangle stars Vega and Altair. The star Deneb bobs in the middle of this river of stars that meanders through the Summer Triangle, arcing across the sky from horizon to horizon. Although every star that you see with the unaided eye is actually a member of our Milky Way galaxy, the term Milky Way often refers to the cross-sectional view of the galactic disk, whereby innumerable far-off suns congregate into a cloudy trail of stars.
Make friends with the Summer Triangle and its three brilliant stars – Vega, Deneb and Altair – tonight. Note the great boulevard of stars that streams right through the Summer Triangle on an inky-dark night. That’s actually an edgewise view into the flat disk of our Milky Way galaxy.
By the way, you can see the Summer Triangle in the Southern Hemisphere, too – although there do you call it the Winter Triangle? I wonder. South of the equator, people see an upside-down version of tonight’s sky scene, in contrast to our northern perspective. Late tonight, Southern Hemisphere residents will see Altair at the top of the Summer Triangle, and Vega and Deneb sparkling at the bottom.
Summer Triangle and the top of the Louvre Pyramid from EarthSky Facebook friend VegaStar Carpentier in Paris. Thanks, VegaStar!
Bottom line: The Summer Triangle asterism can be seen overhead at late evening now. The Summer Triangle isn’t a constellation, but it’s still very prominent. It’s three bright stars in three different constellations. These stars are Vega in the constellation Lyra the Harp, Deneb in the constellation Cygnus the Swan, and Altair in the constellation Aquila the Eagle.
from EarthSky https://ift.tt/2TCRN6r
We’ve recently seen Orion’s return to the east before dawn, which means our northern summer is beginning to draw to a close. But the Summer Triangle asterism still rules the skies. It pops out first thing at nightfall and climbs highest up for the night at late evening. From mid-northern latitudes, Vega – the Summer Triangle’s brightest star – shines high overhead around 10 p.m. local daylight saving time (9 p.m. local standard time). Altair resides to the southeast (lower left) of Vega, and Deneb lies to Vega’s east (left).
The Summer Triangle is not a constellation. It is three bright stars in three different constellations, as the wonderful photo below – by Susan Jensen in Odessa, Washington – shows.
Here is the Summer Triangle asterism – 3 bright stars in 3 different constellations – as photographed by Susan Jensen in Odessa, Washington.
As the stars drift westward during the night, Deneb will swing upward to replace Vega as the overhead star some two hours later. Of course, the stars aren’t really moving. It’s the Earth’s rotation that causes the stars to move westward during the night, and the sun to go westward during the day.
Great rift of Milky Way passes through the constellation Cassiopeia and the Summer Triangle. Click here for a larger photo
Because the three stars making up the Summer Triangle are 1st-magnitude stars, you can easily see the brilliant Summer Triangle on moonlit nights. However, you need a dark sky free of moonlight to see the great swath of stars known as the Milky Way passing in between the Summer Triangle stars Vega and Altair. The star Deneb bobs in the middle of this river of stars that meanders through the Summer Triangle, arcing across the sky from horizon to horizon. Although every star that you see with the unaided eye is actually a member of our Milky Way galaxy, the term Milky Way often refers to the cross-sectional view of the galactic disk, whereby innumerable far-off suns congregate into a cloudy trail of stars.
Make friends with the Summer Triangle and its three brilliant stars – Vega, Deneb and Altair – tonight. Note the great boulevard of stars that streams right through the Summer Triangle on an inky-dark night. That’s actually an edgewise view into the flat disk of our Milky Way galaxy.
By the way, you can see the Summer Triangle in the Southern Hemisphere, too – although there do you call it the Winter Triangle? I wonder. South of the equator, people see an upside-down version of tonight’s sky scene, in contrast to our northern perspective. Late tonight, Southern Hemisphere residents will see Altair at the top of the Summer Triangle, and Vega and Deneb sparkling at the bottom.
Summer Triangle and the top of the Louvre Pyramid from EarthSky Facebook friend VegaStar Carpentier in Paris. Thanks, VegaStar!
Bottom line: The Summer Triangle asterism can be seen overhead at late evening now. The Summer Triangle isn’t a constellation, but it’s still very prominent. It’s three bright stars in three different constellations. These stars are Vega in the constellation Lyra the Harp, Deneb in the constellation Cygnus the Swan, and Altair in the constellation Aquila the Eagle.
Study claims young people up to seven times more likely to contract coronavirus
Teens and young adults who use e-cigarettes could be five to seven times more likely than non-smokers to catch coronavirus, new research suggests. The study linked vaping to an increased risk in young people developing symptoms such as coughing, fever, tiredness and difficulty breathing. Findings come after researchers at the University of Tasmania analysed survey responses from over 4,351 people aged between 13 and 24, who smoked both tobacco and e-cigarettes.
Despite the headlines, this “7 times more likely” figure includes people who’ve used tobacco and e-cigarettes “ever” alongside with those who’ve just used both in the last 30 days. When looking at the individuals who only used e-cigarettes in the last 30 days, there was no significant increase in COVID-19 diagnosis. Find out more at The Independent.
Three new genetic variants linked to male breast cancer
Research funded by Breast Cancer Now has discovered three new genetic changes that increase the risk of breast cancer in men. New findings bring the total number of known common genetic changes linked to male breast cancer to five. Around 370 men are diagnosed with breast cancer every year in the UK, with 80 dying of the disease. Scientists say the findings could lead to better risk testing for male breast cancer, as well as development of new preventative drugs. Full story at The Institute of Cancer Research.
Half of under-50s delay bowel cancer checks
iNews has reported the findings from Bowel Cancer UK showing that half of under-50s in Britain are unaware they could develop bowel cancer, despite displaying “red flag” symptoms. According to figures, a third of people in this age category delay seeing their GP for three months, with 40% visiting their doctor at least three times before being referred for further tests. The charity warns that delays in seeking medical advice is leading to younger people being diagnosed with the disease at an advanced stage. You can find out how to safely access your GP services on the NHS website.
Shorter radiotherapy just as effective for fighting cancer
The Times reports that early-stage cancer patients are benefiting from modified radiotherapy treatment across the NHS in response to the pandemic. Researchers have shown that a smaller number of larger radiotherapy doses can cut radiotherapy treatment from four weeks to five days, meaning patients need fewer hospital visits. The decision has been backed up in a pioneering study by the Institute of Cancer Research, which found women with early-stage breast cancer can be successfully treated in this way.
And finally…
A “game-changing” scan that creates a GPS-style map of patients’ lungs is being used to detect early signs of cancer. The electromagnetic navigation bronchoscopy (ENB) uses GPS-like technology to build a 3D image of the lungs, highlighting tumours that are too small or awkwardly placed to be spotted by routine scans. Glan Clwyd Hospital in Denbighshire has become the second hospital in the UK to use the technology, after St Bartholomew’s Hospital in London. Full story at BBC.
Scarlett Sangster is a writer for PA Media Group
from Cancer Research UK – Science blog https://ift.tt/2Y4ULnv
Study claims young people up to seven times more likely to contract coronavirus
Teens and young adults who use e-cigarettes could be five to seven times more likely than non-smokers to catch coronavirus, new research suggests. The study linked vaping to an increased risk in young people developing symptoms such as coughing, fever, tiredness and difficulty breathing. Findings come after researchers at the University of Tasmania analysed survey responses from over 4,351 people aged between 13 and 24, who smoked both tobacco and e-cigarettes.
Despite the headlines, this “7 times more likely” figure includes people who’ve used tobacco and e-cigarettes “ever” alongside with those who’ve just used both in the last 30 days. When looking at the individuals who only used e-cigarettes in the last 30 days, there was no significant increase in COVID-19 diagnosis. Find out more at The Independent.
Three new genetic variants linked to male breast cancer
Research funded by Breast Cancer Now has discovered three new genetic changes that increase the risk of breast cancer in men. New findings bring the total number of known common genetic changes linked to male breast cancer to five. Around 370 men are diagnosed with breast cancer every year in the UK, with 80 dying of the disease. Scientists say the findings could lead to better risk testing for male breast cancer, as well as development of new preventative drugs. Full story at The Institute of Cancer Research.
Half of under-50s delay bowel cancer checks
iNews has reported the findings from Bowel Cancer UK showing that half of under-50s in Britain are unaware they could develop bowel cancer, despite displaying “red flag” symptoms. According to figures, a third of people in this age category delay seeing their GP for three months, with 40% visiting their doctor at least three times before being referred for further tests. The charity warns that delays in seeking medical advice is leading to younger people being diagnosed with the disease at an advanced stage. You can find out how to safely access your GP services on the NHS website.
Shorter radiotherapy just as effective for fighting cancer
The Times reports that early-stage cancer patients are benefiting from modified radiotherapy treatment across the NHS in response to the pandemic. Researchers have shown that a smaller number of larger radiotherapy doses can cut radiotherapy treatment from four weeks to five days, meaning patients need fewer hospital visits. The decision has been backed up in a pioneering study by the Institute of Cancer Research, which found women with early-stage breast cancer can be successfully treated in this way.
And finally…
A “game-changing” scan that creates a GPS-style map of patients’ lungs is being used to detect early signs of cancer. The electromagnetic navigation bronchoscopy (ENB) uses GPS-like technology to build a 3D image of the lungs, highlighting tumours that are too small or awkwardly placed to be spotted by routine scans. Glan Clwyd Hospital in Denbighshire has become the second hospital in the UK to use the technology, after St Bartholomew’s Hospital in London. Full story at BBC.
Scarlett Sangster is a writer for PA Media Group
from Cancer Research UK – Science blog https://ift.tt/2Y4ULnv
Images of Occator Crater on Ceres, which is the biggest dwarf planet in the asteroid belt between Mars and Jupiter. The white areas in the crater are salt deposits. Numerous images – seen in false-color – were pieced together here to create this animated view. Image via NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA.
As the Dawn spacecraft was approaching Ceres in 2015, it spied some mysterious bright spots on the surface of this dwarf planet. Something on Ceres was so highly reflective that, for a time, onlookers joked about alien lights. Scientists were puzzled at first, wondering what was causing the reflectivity. It turned out there are multiple bright spots on Ceres, and they’re now known to be salt deposits on this little world’s surface, mostly composed of sodium carbonate. Scientists said the spots likely came from liquid that had percolated up to Ceres’ surface and evaporated, leaving behind a salt crust. But percolated up from where? In October 2018, as Dawn’s mission was ending, the spacecraft dipped to less than 22 miles (35 km) above Ceres’ surface. The craft saw new details in the bright areas that have now enabled scientists to explain the bright spots’ origins.
Dawn scientists now say that the salty liquid on Ceres’ surface came from a reservoir of brine, or salt-enriched water, deep in Ceres’ interior. Scientists say this brine reservoir is about 25 miles (40 km) deep and hundreds of miles wide. Ceres itself is less than 600 miles across (1,000 km) across. So, in other words, Ceres is now understood to have a relatively vast interior reservoir of briny water.
The findings, which also reveal the extent of geologic activity in Occator Crater – home of Ceres’ most famous bright spots – appear in a special collection of papers published by Nature Astronomy, Nature Geoscience, and Nature Communications on August 10, 2020.
In 2015, as NASA’s Dawn spacecraft approached dwarf planet Ceres, it saw 2 strange bright spots on Ceres’ surface. Onlookers joked about “alien headlights,” but couldn’t explain the spots yet. Now they’re known to be relatively recent salt deposits. This image is from February 19, 2015, acquired from a distance of nearly 29,000 miles (46,000 km). It revealed that the brightest spot on Ceres has a dimmer companion, which lies in the same crater, now called Occator Crater. Image via NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA.
Ceres’ bright spots from just 240 miles (385 km) above its surface (lower than the International Space Station is above Earth). Image via NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA.
An image of Occator Crater – and the bright spots – draped over a digital terrain model, providing a 3-D-like perspective view. Image via NASA/ JPL.
Ceres – reclassified as a dwarf planet by the International Astronomical Union (IAU) in 2006, at the same time Pluto was demoted from full planet status – was formerly called asteroid Ceres and was the first asteroid to have been discovered in 1801.
There were hints of bright regions on Ceres long before Dawn’s arrival in 2015. Peering through telescopes, scientists had noticed diffuse bright areas of an unknown nature on the dwarf planets. The scientists’ statement said they:
… knew that micrometeorites frequently pelt the surface of Ceres, roughing it up and leaving debris. Over time, that sort of action should darken these bright areas. So their brightness indicates that they likely are young. Trying to understand the source of the areas, and how the material could be so new, was a main focus of Dawn’s final extended mission, from 2017 to 2018.
The research not only confirmed that the bright regions are young, some less than 2 million years old. It also found that the geologic activity driving these deposits could be ongoing. This conclusion depended on scientists making a key discovery: salt compounds (sodium chloride chemically bound with water and ammonium chloride) concentrated in Cerealia Facula. The scientists explained:
On Ceres’ surface, salts bearing water quickly dehydrate, within hundreds of years. But Dawn’s measurements show they still have water, so the fluids must have reached the surface very recently. This is evidence both for the presence of liquid below the region of Occator Crater and ongoing transfer of material from the deep interior to the surface.
In our solar system, icy geologic activity happens mainly on icy moons, where it’s driven by their gravitational interactions with their larger planets. But that’s not the case with the movement of brines to the surface of Ceres, because this little world isn’t particularly near any large bodies in space that might be pulling on it. Instead, the scientists found two main pathways that allow liquids from Ceres’ interior to reach its surface. Dawn principal investigator Carol Raymond said:
For the large deposit at Cerealia Facula, the bulk of the salts were supplied from a slushy area just beneath the surface that was melted by the heat of the impact that formed the crater about 20 million years ago. The impact heat subsided after a few million years; however, the impact also created large fractures that could reach the deep, long-lived reservoir, allowing brine to continue percolating to the surface.
The discovery of this presumably ongoing activity on Ceres – this movement of briny water from its interior to its surface – suggests that other large ice-rich bodies in our solar system that are not moons might also be active.
This mosaic image uses false color to highlight the recently exposed brine, or salty liquids, that were pushed up from a deep reservoir under Ceres’ crust. In this view of a region of Occator Crater, they appear reddish. Image via NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Dawn is the only spacecraft ever to orbit two extraterrestrial destinations: Ceres and the giant asteroid Vesta. This dual mission was made possible by Dawn’s ion propulsion system. The scientists’ statement explained:
When Dawn used the last of a key fuel, hydrazine, for a system that controls its orientation, it was neither able to point to Earth for communications nor to point its solar arrays at the sun to produce electrical power. Because Ceres was found to have organic materials on its surface and liquid below the surface, planetary protection rules required Dawn to be placed in a long-duration orbit that will prevent it from impacting the dwarf planet for decades.
Dawn accomplished far more than we hoped when it embarked on its extraordinary extraterrestrial expedition. These exciting new discoveries from the end of its long and productive mission are a wonderful tribute to this remarkable interplanetary explorer.
This mosaic of Ceres’ Occator Crater is composed of images NASA’s Dawn mission captured on its second extended mission, in 2018. Bright pits and mounds (foreground) were formed by salty liquid released as Occator’s water-rich floor froze after the crater-forming impact about 20 million years ago. Image via NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA/ USRA/ LPI.
Bottom line: Scientists studying data from spacecraft Dawn now say that the salt deposits on Ceres’ surface came from a reservoir of brine, or salt-enriched water, deep in the dwarf planet’s interior. This brine reservoir is estimated to be about 25 miles (40 km) deep and hundreds of miles wide … remarkable on a little world less than 600 miles (1,000 km) across.
Images of Occator Crater on Ceres, which is the biggest dwarf planet in the asteroid belt between Mars and Jupiter. The white areas in the crater are salt deposits. Numerous images – seen in false-color – were pieced together here to create this animated view. Image via NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA.
As the Dawn spacecraft was approaching Ceres in 2015, it spied some mysterious bright spots on the surface of this dwarf planet. Something on Ceres was so highly reflective that, for a time, onlookers joked about alien lights. Scientists were puzzled at first, wondering what was causing the reflectivity. It turned out there are multiple bright spots on Ceres, and they’re now known to be salt deposits on this little world’s surface, mostly composed of sodium carbonate. Scientists said the spots likely came from liquid that had percolated up to Ceres’ surface and evaporated, leaving behind a salt crust. But percolated up from where? In October 2018, as Dawn’s mission was ending, the spacecraft dipped to less than 22 miles (35 km) above Ceres’ surface. The craft saw new details in the bright areas that have now enabled scientists to explain the bright spots’ origins.
Dawn scientists now say that the salty liquid on Ceres’ surface came from a reservoir of brine, or salt-enriched water, deep in Ceres’ interior. Scientists say this brine reservoir is about 25 miles (40 km) deep and hundreds of miles wide. Ceres itself is less than 600 miles across (1,000 km) across. So, in other words, Ceres is now understood to have a relatively vast interior reservoir of briny water.
The findings, which also reveal the extent of geologic activity in Occator Crater – home of Ceres’ most famous bright spots – appear in a special collection of papers published by Nature Astronomy, Nature Geoscience, and Nature Communications on August 10, 2020.
In 2015, as NASA’s Dawn spacecraft approached dwarf planet Ceres, it saw 2 strange bright spots on Ceres’ surface. Onlookers joked about “alien headlights,” but couldn’t explain the spots yet. Now they’re known to be relatively recent salt deposits. This image is from February 19, 2015, acquired from a distance of nearly 29,000 miles (46,000 km). It revealed that the brightest spot on Ceres has a dimmer companion, which lies in the same crater, now called Occator Crater. Image via NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA.
Ceres’ bright spots from just 240 miles (385 km) above its surface (lower than the International Space Station is above Earth). Image via NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA.
An image of Occator Crater – and the bright spots – draped over a digital terrain model, providing a 3-D-like perspective view. Image via NASA/ JPL.
Ceres – reclassified as a dwarf planet by the International Astronomical Union (IAU) in 2006, at the same time Pluto was demoted from full planet status – was formerly called asteroid Ceres and was the first asteroid to have been discovered in 1801.
There were hints of bright regions on Ceres long before Dawn’s arrival in 2015. Peering through telescopes, scientists had noticed diffuse bright areas of an unknown nature on the dwarf planets. The scientists’ statement said they:
… knew that micrometeorites frequently pelt the surface of Ceres, roughing it up and leaving debris. Over time, that sort of action should darken these bright areas. So their brightness indicates that they likely are young. Trying to understand the source of the areas, and how the material could be so new, was a main focus of Dawn’s final extended mission, from 2017 to 2018.
The research not only confirmed that the bright regions are young, some less than 2 million years old. It also found that the geologic activity driving these deposits could be ongoing. This conclusion depended on scientists making a key discovery: salt compounds (sodium chloride chemically bound with water and ammonium chloride) concentrated in Cerealia Facula. The scientists explained:
On Ceres’ surface, salts bearing water quickly dehydrate, within hundreds of years. But Dawn’s measurements show they still have water, so the fluids must have reached the surface very recently. This is evidence both for the presence of liquid below the region of Occator Crater and ongoing transfer of material from the deep interior to the surface.
In our solar system, icy geologic activity happens mainly on icy moons, where it’s driven by their gravitational interactions with their larger planets. But that’s not the case with the movement of brines to the surface of Ceres, because this little world isn’t particularly near any large bodies in space that might be pulling on it. Instead, the scientists found two main pathways that allow liquids from Ceres’ interior to reach its surface. Dawn principal investigator Carol Raymond said:
For the large deposit at Cerealia Facula, the bulk of the salts were supplied from a slushy area just beneath the surface that was melted by the heat of the impact that formed the crater about 20 million years ago. The impact heat subsided after a few million years; however, the impact also created large fractures that could reach the deep, long-lived reservoir, allowing brine to continue percolating to the surface.
The discovery of this presumably ongoing activity on Ceres – this movement of briny water from its interior to its surface – suggests that other large ice-rich bodies in our solar system that are not moons might also be active.
This mosaic image uses false color to highlight the recently exposed brine, or salty liquids, that were pushed up from a deep reservoir under Ceres’ crust. In this view of a region of Occator Crater, they appear reddish. Image via NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Dawn is the only spacecraft ever to orbit two extraterrestrial destinations: Ceres and the giant asteroid Vesta. This dual mission was made possible by Dawn’s ion propulsion system. The scientists’ statement explained:
When Dawn used the last of a key fuel, hydrazine, for a system that controls its orientation, it was neither able to point to Earth for communications nor to point its solar arrays at the sun to produce electrical power. Because Ceres was found to have organic materials on its surface and liquid below the surface, planetary protection rules required Dawn to be placed in a long-duration orbit that will prevent it from impacting the dwarf planet for decades.
Dawn accomplished far more than we hoped when it embarked on its extraordinary extraterrestrial expedition. These exciting new discoveries from the end of its long and productive mission are a wonderful tribute to this remarkable interplanetary explorer.
This mosaic of Ceres’ Occator Crater is composed of images NASA’s Dawn mission captured on its second extended mission, in 2018. Bright pits and mounds (foreground) were formed by salty liquid released as Occator’s water-rich floor froze after the crater-forming impact about 20 million years ago. Image via NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA/ USRA/ LPI.
Bottom line: Scientists studying data from spacecraft Dawn now say that the salt deposits on Ceres’ surface came from a reservoir of brine, or salt-enriched water, deep in the dwarf planet’s interior. This brine reservoir is estimated to be about 25 miles (40 km) deep and hundreds of miles wide … remarkable on a little world less than 600 miles (1,000 km) across.
