Comet A3 is brightening. Will it be the comet of the year?

Here’s a star chart showing Comet A3 Tsuchinshan-ATLAS around September 19, 2024, from the Miami, Florida, area. The comet will be low on the eastern horizon just before sunrise. Image via Stellarium/ Eddie Irizarry.

A bright comet for September and October?

The rumors of Comet A3 Tsuchinshan-ATLAS’s demise were premature. Earlier in 2024, there were reports that the comet was breaking up. But instead, the comet is now coming into morning skies and appears to be in good shape. Its current brightness would put it just within reach of the unaided eye from a dark, country site, at magnitude 5.5. With ordinary binoculars, it should be possible to pick up now. And it’s getting brighter.

Despite the previous reports that the comet might be disintegrating, the latest observations by sun-observing satellites and amateur astronomers indicate the comet is still very much alive. In fact, comet expert Terry Lovejoy was able to photograph the comet on the morning of September 11, 2024, from Queensland, Australia. He used a camera with a 135mm f1.8 lens.

Meanwhile, observer Colin Drescher was also able to capture some of the first recovery images using just a small digital telescope.

How bright will it get?

Comets are unpredictable. And there’s no way to know at this time exactly how bright Comet A3 will become. But preliminary estimates suggest it might reach magnitude 4 to 3 (the lower the number, the brighter) around the time of its closest approach to the sun – or perihelion – on September 27.

The exciting part might come afterwards. It could grow as bright as magnitude 2.5 to 2 during closest approach to Earth on October 12. Or maybe even slightly brighter if we are lucky (or fainter if we’re unlucky), since comet behavior is so difficult to predict.

So Comet A3 isn’t going to be a Comet of the Century. But if it continues to perform well, it might be the brightest comet of the year.

Efrain Morales captured this image of Comet A3 Tsuchinshan-ATLAS from Puerto Rico on July 8, 2024. Image via Efrain Morales/ Eddie Irizarry.

How to see Comet A3 in September

Observers in the Southern Hemisphere have the best seats to view the comet during the first half of September. Observers closer to Earth’s equator will get their first opportunities from mid-September to the end of the month. And for those in the lower United States, the first dawn views of Comet A3 might be possible starting around September 18 to 20. It’ll get a bit easier to locate by the end of the month.

One caveat: observers would require a clear, unobstructed view of the eastern horizon.

By the end of September, Comet A3 will gradually make the transition from the brief dawn appearance to the western skies at dusk. It may become visible starting around October 12, which is the date of closest approach to Earth. If it survives its encounter with the sun, the comet should put on a good show by mid-October.

Comet A3 in October

After the comet gets closest to the sun, it will swing around near Earth. But as it does so, it passes almost directly between Earth and the sun, making it challenging to view. In early October, the comet will be in the dawn sky in Leo and near the constellations Hydra and Crater.

Starting from October 13 to 14, Comet A3 will be easier to spot on the following evenings. That’s thanks to the comet’s great speed, which will cause it to appear higher in the western sky on the following nights.

Then in late October, as it appears on the other side of the sun, it will move into the evening sky, passing through Serpens Caput and into Ophiuchus.

The turquoise line represents the path of Comet C/2023 A3 into the inner solar system. The comet will be closest to the sun on September 28, 2024, and closest to Earth in October 2024. Image via University of Arizona/ CSS/ D. Rankin.

Finder charts for Comet Tsuchinshan-ATLAS

If we are fortunate, the comet will grace our sky from October 14 to 24. Look to the west shortly after sunset for Comet Tsuchinshan–ATLAS. Chart by John Jardine Goss/ EarthSky.

Comet C/2023 A3 on September 28, 2024 (perihelion). Facing east just before sunrise. Illustration by Eddie Irizarry using Stellarium.

Comet C/2023 A3 on October 14, 2024, one day after closest approach to Earth. Facing a western unobstructed horizon just after sunset. Illustration by Eddie Irizarry using Stellarium.

Around October 17, 2024, comet C/2023 A3 (Tsuchinshan-ATLAS) might be easier to see in the western sky, as the comet gets higher each subsequent night. Illustration by Eddie Irizarry using Stellarium.

A speedy ball of ice and dust

Comet Tsuchinshan-ATLAS is blazingly speedy. It’s tearing through the inner solar system at 180,610 miles (290,664 km) per hour or 80.74 km per second, relative to Earth. And you can see its amazing speed with a small telescope. You can watch the comet’s location gradually change by comparing its exact position against background stars just 15 minutes later.

Comet A3 Tsuchinshan-ATLAS’s disintegration rumors

Comet A3 Tsuchinshan-ATLAS hasn’t been acting as people expected it to. As it was approaching the inner solar system in early 2024, it wasn’t brightening as much as expected. And then a study suggested the cometary nucleus was fragmenting.

The paper’s author, Zdenek Sekanina, a Czech-American astronomer and comet expert at NASA’s Jet Propulsion Laboratory, said on July 8, 2024, the comet entered an advanced phase of fragmentation. He said the end of Comet Tsuchinshan-ATLAS was inevitable.

However, comets are notorious for being erratic and unpredictable. And this one proved to be as well.

Discovery and naming

The Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in South Africa discovered Comet C/2023 A3 on February 22, 2023. Additionally, observers at Purple Mountain (Zijin Shin or Tsuchinshan) Observatory in China found the comet independently on images from January 9, 2023. Therefore, the comet also has the nickname Tsuchinshan-ATLAS.

At discovery, the comet was still 7.3 astronomical units (AU) from the sun, and shining at a dim magnitude 18.

Preliminary analysis of its trajectory suggests comet “A3” completes an orbit around the sun every 80,660 years.

View at EarthSky Community Photos. | Filipp Romanov captured these images showing movement of the new comet, originally labeled A10SVYR, and now officially C/2023 A3. Filipp took these images confirming the new comet with remote iTelescopes in Chile and Australia on February 24, 2023. Thank you, Filipp!

Bottom line: Comet A3 Tsuchinshan-ATLAS survived its rumored disintegration and may become the brightest comet of the year this September and October.

Source: Inevitable Endgame of Comet Tsuchinshan-ATLAS (C/2023 A3)

The post Comet A3 is brightening. Will it be the comet of the year? first appeared on EarthSky.

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Here’s a star chart showing Comet A3 Tsuchinshan-ATLAS around September 19, 2024, from the Miami, Florida, area. The comet will be low on the eastern horizon just before sunrise. Image via Stellarium/ Eddie Irizarry.

A bright comet for September and October?

The rumors of Comet A3 Tsuchinshan-ATLAS’s demise were premature. Earlier in 2024, there were reports that the comet was breaking up. But instead, the comet is now coming into morning skies and appears to be in good shape. Its current brightness would put it just within reach of the unaided eye from a dark, country site, at magnitude 5.5. With ordinary binoculars, it should be possible to pick up now. And it’s getting brighter.

Despite the previous reports that the comet might be disintegrating, the latest observations by sun-observing satellites and amateur astronomers indicate the comet is still very much alive. In fact, comet expert Terry Lovejoy was able to photograph the comet on the morning of September 11, 2024, from Queensland, Australia. He used a camera with a 135mm f1.8 lens.

Meanwhile, observer Colin Drescher was also able to capture some of the first recovery images using just a small digital telescope.

How bright will it get?

Comets are unpredictable. And there’s no way to know at this time exactly how bright Comet A3 will become. But preliminary estimates suggest it might reach magnitude 4 to 3 (the lower the number, the brighter) around the time of its closest approach to the sun – or perihelion – on September 27.

The exciting part might come afterwards. It could grow as bright as magnitude 2.5 to 2 during closest approach to Earth on October 12. Or maybe even slightly brighter if we are lucky (or fainter if we’re unlucky), since comet behavior is so difficult to predict.

So Comet A3 isn’t going to be a Comet of the Century. But if it continues to perform well, it might be the brightest comet of the year.

Efrain Morales captured this image of Comet A3 Tsuchinshan-ATLAS from Puerto Rico on July 8, 2024. Image via Efrain Morales/ Eddie Irizarry.

How to see Comet A3 in September

Observers in the Southern Hemisphere have the best seats to view the comet during the first half of September. Observers closer to Earth’s equator will get their first opportunities from mid-September to the end of the month. And for those in the lower United States, the first dawn views of Comet A3 might be possible starting around September 18 to 20. It’ll get a bit easier to locate by the end of the month.

One caveat: observers would require a clear, unobstructed view of the eastern horizon.

By the end of September, Comet A3 will gradually make the transition from the brief dawn appearance to the western skies at dusk. It may become visible starting around October 12, which is the date of closest approach to Earth. If it survives its encounter with the sun, the comet should put on a good show by mid-October.

Comet A3 in October

After the comet gets closest to the sun, it will swing around near Earth. But as it does so, it passes almost directly between Earth and the sun, making it challenging to view. In early October, the comet will be in the dawn sky in Leo and near the constellations Hydra and Crater.

Starting from October 13 to 14, Comet A3 will be easier to spot on the following evenings. That’s thanks to the comet’s great speed, which will cause it to appear higher in the western sky on the following nights.

Then in late October, as it appears on the other side of the sun, it will move into the evening sky, passing through Serpens Caput and into Ophiuchus.

The turquoise line represents the path of Comet C/2023 A3 into the inner solar system. The comet will be closest to the sun on September 28, 2024, and closest to Earth in October 2024. Image via University of Arizona/ CSS/ D. Rankin.

Finder charts for Comet Tsuchinshan-ATLAS

If we are fortunate, the comet will grace our sky from October 14 to 24. Look to the west shortly after sunset for Comet Tsuchinshan–ATLAS. Chart by John Jardine Goss/ EarthSky.

Comet C/2023 A3 on September 28, 2024 (perihelion). Facing east just before sunrise. Illustration by Eddie Irizarry using Stellarium.

Comet C/2023 A3 on October 14, 2024, one day after closest approach to Earth. Facing a western unobstructed horizon just after sunset. Illustration by Eddie Irizarry using Stellarium.

Around October 17, 2024, comet C/2023 A3 (Tsuchinshan-ATLAS) might be easier to see in the western sky, as the comet gets higher each subsequent night. Illustration by Eddie Irizarry using Stellarium.

A speedy ball of ice and dust

Comet Tsuchinshan-ATLAS is blazingly speedy. It’s tearing through the inner solar system at 180,610 miles (290,664 km) per hour or 80.74 km per second, relative to Earth. And you can see its amazing speed with a small telescope. You can watch the comet’s location gradually change by comparing its exact position against background stars just 15 minutes later.

Comet A3 Tsuchinshan-ATLAS’s disintegration rumors

Comet A3 Tsuchinshan-ATLAS hasn’t been acting as people expected it to. As it was approaching the inner solar system in early 2024, it wasn’t brightening as much as expected. And then a study suggested the cometary nucleus was fragmenting.

The paper’s author, Zdenek Sekanina, a Czech-American astronomer and comet expert at NASA’s Jet Propulsion Laboratory, said on July 8, 2024, the comet entered an advanced phase of fragmentation. He said the end of Comet Tsuchinshan-ATLAS was inevitable.

However, comets are notorious for being erratic and unpredictable. And this one proved to be as well.

Discovery and naming

The Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in South Africa discovered Comet C/2023 A3 on February 22, 2023. Additionally, observers at Purple Mountain (Zijin Shin or Tsuchinshan) Observatory in China found the comet independently on images from January 9, 2023. Therefore, the comet also has the nickname Tsuchinshan-ATLAS.

At discovery, the comet was still 7.3 astronomical units (AU) from the sun, and shining at a dim magnitude 18.

Preliminary analysis of its trajectory suggests comet “A3” completes an orbit around the sun every 80,660 years.

View at EarthSky Community Photos. | Filipp Romanov captured these images showing movement of the new comet, originally labeled A10SVYR, and now officially C/2023 A3. Filipp took these images confirming the new comet with remote iTelescopes in Chile and Australia on February 24, 2023. Thank you, Filipp!

Bottom line: Comet A3 Tsuchinshan-ATLAS survived its rumored disintegration and may become the brightest comet of the year this September and October.

Source: Inevitable Endgame of Comet Tsuchinshan-ATLAS (C/2023 A3)

The post Comet A3 is brightening. Will it be the comet of the year? first appeared on EarthSky.

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Earth to get an asteroid mini-moon for 2 months

Newly-discovered #asteroid 2024 PT5 is about to undergo a "mini-moon event" when its geocentric energy becomes negative from September 29 – November 25.https://t.co/sAo1qSRu3J pic.twitter.com/pVYAmSbkCF

— Tony Dunn (@tony873004) September 10, 2024

Asteroid mini-moon animation via Tony Dunn on X.

Earth to get an asteroid mini-moon for 2 months

Earth’s gravity will temporarily capture a newly discovered asteroid named 2024 PT5, creating a mini-moon. According to researchers Carlos de la Fuente Marcos and Raúl de la Fuente Marcos, the asteroid should loop around Earth from September 29 until November 25, 2024. However, the asteroid will never complete one revolution of Earth, so it’s considered a temporarily captured flyby as opposed to a temporarily captured orbiter. Either way, this asteroid mini-moon will hang around until it once again breaks loose from Earth’s grasp.

The ATLAS survey in South Africa discovered the asteroid on August 7, 2024.

The scientists published their study in the non-peer-reviewed Research Notes of the AAS in September 2024.

Mini-moon and asteroid PT5

The asteroid and soon-to-be mini-moon is approximately 33 feet (10 meters) in size. It’s likely part of a population of near-Earth asteroids called Arjunas. These objects have orbits around the sun that are similar to Earth’s. Asteroid 2024 PT5’s close approach to our planet at a relatively low velocity is what will allow Earth’s gravity to temporarily alter its path. According to the study, for 56.6 days the little asteroid will change from orbiting the sun to orbiting Earth. But then the sun pulls it back into a heliocentric orbit. The asteroid will then have another somewhat close flyby of Earth on January 9, 2025, before:

leaving the neighborhood of Earth shortly afterward, until its next return in 2055.

From September 29 to November 25, 2024, Earth will have an asteroid mini-moon. That’s when the newly discovered asteroid 2024 PT5 will get close enough to Earth to temporarily be drawn in for a “temporarily captured flyby”. Image via Tony Dunn on X.

Will you see it?

Unfortunately, our new little mini-moon will be too dim to see. It will be no brighter than magnitude 22, which is even out of reach of backyard telescopes.

This is not the first time Earth has acquired a mini-moon. In fact, asteroid 2024 PT5 is following a similar course as an earlier asteroid, 2022 NX1. The asteroid 2022 NX1 became a mini-moon of Earth for a brief time in 1981 and 2022. That asteroid will return as a temporary mini-moon again in 2051.

Bottom line: Earth will get a mini-moon for two months when the 33-foot-wide asteroid 2024 PT5 makes a close pass of our planet and makes a temporary loop about us.

Source: A Two-month Mini-moon: 2024 PT5 Captured by Earth from September to November

Read more: Say goodbye to Earth’s mini-moon on February 1 and 2

The post Earth to get an asteroid mini-moon for 2 months first appeared on EarthSky.

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Newly-discovered #asteroid 2024 PT5 is about to undergo a "mini-moon event" when its geocentric energy becomes negative from September 29 – November 25.https://t.co/sAo1qSRu3J pic.twitter.com/pVYAmSbkCF

— Tony Dunn (@tony873004) September 10, 2024

Asteroid mini-moon animation via Tony Dunn on X.

Earth to get an asteroid mini-moon for 2 months

Earth’s gravity will temporarily capture a newly discovered asteroid named 2024 PT5, creating a mini-moon. According to researchers Carlos de la Fuente Marcos and Raúl de la Fuente Marcos, the asteroid should loop around Earth from September 29 until November 25, 2024. However, the asteroid will never complete one revolution of Earth, so it’s considered a temporarily captured flyby as opposed to a temporarily captured orbiter. Either way, this asteroid mini-moon will hang around until it once again breaks loose from Earth’s grasp.

The ATLAS survey in South Africa discovered the asteroid on August 7, 2024.

The scientists published their study in the non-peer-reviewed Research Notes of the AAS in September 2024.

Mini-moon and asteroid PT5

The asteroid and soon-to-be mini-moon is approximately 33 feet (10 meters) in size. It’s likely part of a population of near-Earth asteroids called Arjunas. These objects have orbits around the sun that are similar to Earth’s. Asteroid 2024 PT5’s close approach to our planet at a relatively low velocity is what will allow Earth’s gravity to temporarily alter its path. According to the study, for 56.6 days the little asteroid will change from orbiting the sun to orbiting Earth. But then the sun pulls it back into a heliocentric orbit. The asteroid will then have another somewhat close flyby of Earth on January 9, 2025, before:

leaving the neighborhood of Earth shortly afterward, until its next return in 2055.

From September 29 to November 25, 2024, Earth will have an asteroid mini-moon. That’s when the newly discovered asteroid 2024 PT5 will get close enough to Earth to temporarily be drawn in for a “temporarily captured flyby”. Image via Tony Dunn on X.

Will you see it?

Unfortunately, our new little mini-moon will be too dim to see. It will be no brighter than magnitude 22, which is even out of reach of backyard telescopes.

This is not the first time Earth has acquired a mini-moon. In fact, asteroid 2024 PT5 is following a similar course as an earlier asteroid, 2022 NX1. The asteroid 2022 NX1 became a mini-moon of Earth for a brief time in 1981 and 2022. That asteroid will return as a temporary mini-moon again in 2051.

Bottom line: Earth will get a mini-moon for two months when the 33-foot-wide asteroid 2024 PT5 makes a close pass of our planet and makes a temporary loop about us.

Source: A Two-month Mini-moon: 2024 PT5 Captured by Earth from September to November

Read more: Say goodbye to Earth’s mini-moon on February 1 and 2

The post Earth to get an asteroid mini-moon for 2 months first appeared on EarthSky.

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Human-made meteor shower could hit Earth in a decade

In this 1-minute video, EarthSky’s Will Triggs tells you about the human-made meteor shower that could be on its way to Earth.

• In 2022, the DART spacecraft struck a small asteroid as part of a test to see if deflecting asteroids is a possibility for planetary defense.
• The impact blasted rocks and dust from the asteroid’s surface.
• Now, it seems, this asteroid debris might strike us. But don’t worry. It’ll burn up in Earth’s atmosphere, creating a meteor shower.

Human-made meteor shower from DART impact

Astronomers talked for years about possible methods of planetary defense: ways to deflect an asteroid on a collision course with Earth. Then, in 2022, they tried it. NASA’s DART spacecraft was made to plow into a distant asteroid moon, a tiny body called Dimorphos, successfully nudging it slightly from its path. The test blasted more than 2 million pounds (or nearly 1 million kilograms) of asteroidal rock and dust into space. And now, a new study says this debris – kicked up from asteroid Dimorphos in the name of planetary defense – might enter the realm of space where Earth orbits, causing a meteor shower in our skies. It’ll be the 1st-ever human-made meteor shower. The rocks and dust could hit Mars in as soon as 7 years from now … and strike Earth’s atmosphere within 10 years. There’s no danger. But it could be something to see.

In fact, the paper said:

Larger particles exhibit a marginally greater likelihood of reaching Mars, while smaller particles favor delivery to Earth-moon, although this effect is insignificant.

DART stands for Double-Asteroid Redirection Test.

This image shows plumes of ejecta streaming from the little asteroid moon Dimorphos, after NASA’s DART spacecraft intentionally struck it on September 26, 2022, in the world’s 1st planetary defense test. Each rectangle represents a different level of contrast, allowing scientists to see fine structure in the plumes. By studying these streams of material, scientists say they can learn about the asteroid and the impact process. Image via ASI’s LICIACube/ ESA. Image via ESA.

Striking Mars and Earth

The largest of the debris would only be about the size of a softball. Earth’s thick atmosphere will disintegrate any meteors from this shower, but Mars’ thinner atmosphere might mean some large pieces could make it through.

Co-author Josep M. Trigo-Rodríguez from the Spanish Institute of Space Sciences (CSIC/IEEC) said:

We were amazed to discover that it is possible for some centimeter-sized [less than 1/2 inch-sized] particles to reach the Earth-moon system and produce a new meteor shower.

The study has been accepted for publication in The Planetary Science Journal, and a preprint dated September 2, 2024, is available on arXiv.

Fallout from the DART impact

While the DART mission was successful in its attempt to shift an asteroid off-course, follow-up studies continue. ESA is launching a mission named Hera to continue observations of Dimorphos and its larger parent asteroid Didymos. ESA said:

ESA’s Hera spacecraft will be launched this October to reach Dimorphos and perform a close-up ‘crash scene investigation’, gathering data on the asteroid’s mass, structure and make-up to turn this kinetic impact method of planetary defense into a well understood and repeatable technique.

A co-author of the new study and ESA Hera mission scientist Michael Kueppers said:

The DART impact offers a rare opportunity to investigate the delivery of ejecta to other celestial bodies, thanks to the fact that we know the impact location and that this impact was observed by the Italian LICIACube deployed from DART as well as by Earth-based observers.

We simulated the ejecta to match LICIACube observations using three million particles grouped into three size populations – 10 cm (3.9 inches), 0.5 cm (0.2 inches) and 30 micrometer, or thousandths of a millimeter (1 millimeter equals 0.04 inches) – moving at speeds of 1 to 1000 m/s (2.2 to 2,237 mph) or a faster rate of up to 2 km/s (4,474 mph).

A view of DART impacting asteroid Didymos from Earth.

The first human-made meteor shower

The human-made meteor shower is not a guarantee, but it’s definitely possible. Lead author Eloy Peña-Asensio of the Department of Aerospace Science and Technology, Politecnico di Milano said:

We identified ejecta orbits compatible with the delivery of meteor-producing particles to both Mars and Earth. Our results indicate the possibility of ejecta reaching the gravitational field of Mars in 13 years for launch velocities around 450 m/s (1,000 mph), while faster ejecta launched at 770 m/s (1,722 mph) could reach its vicinity in just seven years. Particles moving above 1.5 km/s (3,355 mph) could reach the Earth-Moon system in a similar timescale.

In the coming decades, meteor observation campaigns will be crucial in determining whether fragments of Dimorphos, resulting from the DART impact, will reach our planet.

If this happens, we will witness the first human-made meteor shower.

A new May meteor shower in our skies

When the meteors hit Earth’s atmosphere, they’ll light up, and the color they emit can give clues to the composition of the rocks and dust. Kueppers said:

The exciting thing is the prospect of identifying and observing meteors linked to the DART impact, either on Earth or perhaps one day even on Mars, with their brightness and color revealing details of their makeup.

As for us Earthly observers, we should expect the meteors in the month of May a decade or so from now. And the shower could return periodically for at least 100 years. However, it will favor those in the Southern Hemisphere. Kueppers said:

Our study includes the distinct orbital characteristics that would distinguish these meteors from comparable ones. The potential meteors created by DART would be slow-moving, primarily visible from the southern hemisphere, and most likely to occur in May.

When the DART spacecraft hit the asteroid Dimorphos in a practice run for defending Earth against asteroids, it released tons of rocks and dust. A new study says that debris will eventually hit Mars and Earth, creating the 1st-ever human-made meteor shower. Image via ESA.

Bottom line: When the DART spacecraft hit the asteroid Dimorphos, it released a torrent of debris that should arrive at Mars and Earth, creating the first human-made meteor shower for the planets.

Source: Delivery of DART Impact Ejecta to Mars and Earth: Opportunity for Meteor Observations

Via ESA

The post Human-made meteor shower could hit Earth in a decade first appeared on EarthSky.

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In this 1-minute video, EarthSky’s Will Triggs tells you about the human-made meteor shower that could be on its way to Earth.

• In 2022, the DART spacecraft struck a small asteroid as part of a test to see if deflecting asteroids is a possibility for planetary defense.
• The impact blasted rocks and dust from the asteroid’s surface.
• Now, it seems, this asteroid debris might strike us. But don’t worry. It’ll burn up in Earth’s atmosphere, creating a meteor shower.

Human-made meteor shower from DART impact

Astronomers talked for years about possible methods of planetary defense: ways to deflect an asteroid on a collision course with Earth. Then, in 2022, they tried it. NASA’s DART spacecraft was made to plow into a distant asteroid moon, a tiny body called Dimorphos, successfully nudging it slightly from its path. The test blasted more than 2 million pounds (or nearly 1 million kilograms) of asteroidal rock and dust into space. And now, a new study says this debris – kicked up from asteroid Dimorphos in the name of planetary defense – might enter the realm of space where Earth orbits, causing a meteor shower in our skies. It’ll be the 1st-ever human-made meteor shower. The rocks and dust could hit Mars in as soon as 7 years from now … and strike Earth’s atmosphere within 10 years. There’s no danger. But it could be something to see.

In fact, the paper said:

Larger particles exhibit a marginally greater likelihood of reaching Mars, while smaller particles favor delivery to Earth-moon, although this effect is insignificant.

DART stands for Double-Asteroid Redirection Test.

This image shows plumes of ejecta streaming from the little asteroid moon Dimorphos, after NASA’s DART spacecraft intentionally struck it on September 26, 2022, in the world’s 1st planetary defense test. Each rectangle represents a different level of contrast, allowing scientists to see fine structure in the plumes. By studying these streams of material, scientists say they can learn about the asteroid and the impact process. Image via ASI’s LICIACube/ ESA. Image via ESA.

Striking Mars and Earth

The largest of the debris would only be about the size of a softball. Earth’s thick atmosphere will disintegrate any meteors from this shower, but Mars’ thinner atmosphere might mean some large pieces could make it through.

Co-author Josep M. Trigo-Rodríguez from the Spanish Institute of Space Sciences (CSIC/IEEC) said:

We were amazed to discover that it is possible for some centimeter-sized [less than 1/2 inch-sized] particles to reach the Earth-moon system and produce a new meteor shower.

The study has been accepted for publication in The Planetary Science Journal, and a preprint dated September 2, 2024, is available on arXiv.

Fallout from the DART impact

While the DART mission was successful in its attempt to shift an asteroid off-course, follow-up studies continue. ESA is launching a mission named Hera to continue observations of Dimorphos and its larger parent asteroid Didymos. ESA said:

ESA’s Hera spacecraft will be launched this October to reach Dimorphos and perform a close-up ‘crash scene investigation’, gathering data on the asteroid’s mass, structure and make-up to turn this kinetic impact method of planetary defense into a well understood and repeatable technique.

A co-author of the new study and ESA Hera mission scientist Michael Kueppers said:

The DART impact offers a rare opportunity to investigate the delivery of ejecta to other celestial bodies, thanks to the fact that we know the impact location and that this impact was observed by the Italian LICIACube deployed from DART as well as by Earth-based observers.

We simulated the ejecta to match LICIACube observations using three million particles grouped into three size populations – 10 cm (3.9 inches), 0.5 cm (0.2 inches) and 30 micrometer, or thousandths of a millimeter (1 millimeter equals 0.04 inches) – moving at speeds of 1 to 1000 m/s (2.2 to 2,237 mph) or a faster rate of up to 2 km/s (4,474 mph).

A view of DART impacting asteroid Didymos from Earth.

The first human-made meteor shower

The human-made meteor shower is not a guarantee, but it’s definitely possible. Lead author Eloy Peña-Asensio of the Department of Aerospace Science and Technology, Politecnico di Milano said:

We identified ejecta orbits compatible with the delivery of meteor-producing particles to both Mars and Earth. Our results indicate the possibility of ejecta reaching the gravitational field of Mars in 13 years for launch velocities around 450 m/s (1,000 mph), while faster ejecta launched at 770 m/s (1,722 mph) could reach its vicinity in just seven years. Particles moving above 1.5 km/s (3,355 mph) could reach the Earth-Moon system in a similar timescale.

In the coming decades, meteor observation campaigns will be crucial in determining whether fragments of Dimorphos, resulting from the DART impact, will reach our planet.

If this happens, we will witness the first human-made meteor shower.

A new May meteor shower in our skies

When the meteors hit Earth’s atmosphere, they’ll light up, and the color they emit can give clues to the composition of the rocks and dust. Kueppers said:

The exciting thing is the prospect of identifying and observing meteors linked to the DART impact, either on Earth or perhaps one day even on Mars, with their brightness and color revealing details of their makeup.

As for us Earthly observers, we should expect the meteors in the month of May a decade or so from now. And the shower could return periodically for at least 100 years. However, it will favor those in the Southern Hemisphere. Kueppers said:

Our study includes the distinct orbital characteristics that would distinguish these meteors from comparable ones. The potential meteors created by DART would be slow-moving, primarily visible from the southern hemisphere, and most likely to occur in May.

When the DART spacecraft hit the asteroid Dimorphos in a practice run for defending Earth against asteroids, it released tons of rocks and dust. A new study says that debris will eventually hit Mars and Earth, creating the 1st-ever human-made meteor shower. Image via ESA.

Bottom line: When the DART spacecraft hit the asteroid Dimorphos, it released a torrent of debris that should arrive at Mars and Earth, creating the first human-made meteor shower for the planets.

Source: Delivery of DART Impact Ejecta to Mars and Earth: Opportunity for Meteor Observations

Via ESA

The post Human-made meteor shower could hit Earth in a decade first appeared on EarthSky.

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Watch 1.8 billion years of plate tectonics on Earth

Watch 1.8 billion years of plate tectonics on Earth in this new animation.

An animation of 1.8 billion years of tectonic movements

Earth has been around for about 4.6 billion years, forming along with the sun during the creation of the solar system. On September 5, 2024, Xianzhi Cao of the Ocean University in China and colleagues shared a new view of the last 1.8 billion years of Earth’s history. Watch this animation of plate tectonics, as the continents we recognize today quickly break apart and join together as they drift across our planet’s surface.

As Alan Collins of the University of Adelaide explained in The Conversation:

It is the first time Earth’s geological record has been used like this, looking so far back in time. This has enabled us to make an attempt at mapping the planet over the last 40% of its history.

The scientists published their new study in the November 2024 issue of the peer-reviewed journal Geoscience Frontiers.

The history of Earth’s tectonic plates

We can spot some of the supercontinents that formed over the history of Earth in the video. Some of the highlights include Pangea, which persisted from around 300 million years ago to 200 million years ago. Before that was Gondwana, which had its heyday around 600 million years ago. Farther back in time was Rodinia, a supercontinent in existence around 1 billion years ago. And toward the end of the video is Nuna, sometimes called Columbia, which extended back to 1.8 billion years ago.

Collins explains why having a map of Earth’s tectonic history is useful to scientists:

Mapping the past plate tectonics of the planet is the first stage in being able to build a complete digital model of Earth through its history.

Such a model will allow us to test hypotheses about Earth’s past. For example, why Earth’s climate has gone through extreme Snowball Earth fluctuations, or why oxygen built up in the atmosphere when it did.

Indeed, it will allow us to much better understand the feedback between the deep planet and the surface systems of Earth that support life as we know it.

Earth’s tectonic plates today

On Earth today, geologists recognize seven major tectonic plates. But there are also a number of minor plates and microplates. These plates are constantly evolving as they push and pull away from each other and erode or build new material. And one day new tectonic plates will emerge and Earth’s evolution will have new chapters.

In Thingvellir National Park in Iceland, people can stroll a path where the North American Plate (right) meets the Eurasian Plate (left). Image via Kelly Kizer Whitt.

Pinnacles National Park is one of the locations on the other end of the giant North American Plate. Here, the western edge of the North American Plate meets the eastern edge of the Pacific Plate. Image via Kelly Kizer Whitt.

Bottom line: Watch a new animation showing Earth’s tectonic and plate boundary evolution over 1.8 billion years and the creation and destruction of numerous supercontinents.

Source: Earth’s tectonic and plate boundary evolution over 1.8 billion years

Via The Conversation

The post Watch 1.8 billion years of plate tectonics on Earth first appeared on EarthSky.

from EarthSky https://ift.tt/LwA9MaG

Watch 1.8 billion years of plate tectonics on Earth in this new animation.

An animation of 1.8 billion years of tectonic movements

Earth has been around for about 4.6 billion years, forming along with the sun during the creation of the solar system. On September 5, 2024, Xianzhi Cao of the Ocean University in China and colleagues shared a new view of the last 1.8 billion years of Earth’s history. Watch this animation of plate tectonics, as the continents we recognize today quickly break apart and join together as they drift across our planet’s surface.

As Alan Collins of the University of Adelaide explained in The Conversation:

It is the first time Earth’s geological record has been used like this, looking so far back in time. This has enabled us to make an attempt at mapping the planet over the last 40% of its history.

The scientists published their new study in the November 2024 issue of the peer-reviewed journal Geoscience Frontiers.

The history of Earth’s tectonic plates

We can spot some of the supercontinents that formed over the history of Earth in the video. Some of the highlights include Pangea, which persisted from around 300 million years ago to 200 million years ago. Before that was Gondwana, which had its heyday around 600 million years ago. Farther back in time was Rodinia, a supercontinent in existence around 1 billion years ago. And toward the end of the video is Nuna, sometimes called Columbia, which extended back to 1.8 billion years ago.

Collins explains why having a map of Earth’s tectonic history is useful to scientists:

Mapping the past plate tectonics of the planet is the first stage in being able to build a complete digital model of Earth through its history.

Such a model will allow us to test hypotheses about Earth’s past. For example, why Earth’s climate has gone through extreme Snowball Earth fluctuations, or why oxygen built up in the atmosphere when it did.

Indeed, it will allow us to much better understand the feedback between the deep planet and the surface systems of Earth that support life as we know it.

Earth’s tectonic plates today

On Earth today, geologists recognize seven major tectonic plates. But there are also a number of minor plates and microplates. These plates are constantly evolving as they push and pull away from each other and erode or build new material. And one day new tectonic plates will emerge and Earth’s evolution will have new chapters.

In Thingvellir National Park in Iceland, people can stroll a path where the North American Plate (right) meets the Eurasian Plate (left). Image via Kelly Kizer Whitt.

Pinnacles National Park is one of the locations on the other end of the giant North American Plate. Here, the western edge of the North American Plate meets the eastern edge of the Pacific Plate. Image via Kelly Kizer Whitt.

Bottom line: Watch a new animation showing Earth’s tectonic and plate boundary evolution over 1.8 billion years and the creation and destruction of numerous supercontinents.

Source: Earth’s tectonic and plate boundary evolution over 1.8 billion years

Via The Conversation

The post Watch 1.8 billion years of plate tectonics on Earth first appeared on EarthSky.

from EarthSky https://ift.tt/LwA9MaG

New dinosaur – a long-necked titanosaur – uncovered in Spain

Artist’s concept of the dinosaur Qunkasaura pintiquiniestra. Image via José Antonio Peñas Artero / University of Lisbon.

A new species of titanosaur – Qunkasaura pintiquiniestra – was discovered near Cuenca, Spain. It lived around 73 million years ago.

The animal’s well-preserved partial skeleton allowed scientists to identify it as a new species.

Two distinct groups of smaller titanosaurs called saltasauroids were found at the site, adding more diversity to the list of dinosaurs roaming Europe during the Cretaceous.

Meet Q. pintiquiniestra, an enormous vegetarian dinosaur from ancient Spain

A new species of titanosaur – a variety of large long-necked plant-eating dinosaur – was recently recovered from a fossil bed near Cuenca, Spain. The newly identified animals lived around 73 million years ago, during the late Cretaceous Period.

Scientists who identified the oversize dino announced their discovery this week in the journal Communications Biology. Their findings were published on September 4, 2024.

And its name is a mouthful. The group called the dinosaur Qunkasaura pintiquiniestra.

A treasure trove of dinosaur fossils unearthed in Spain

In 2007, thousands of fossils were collected at a site called Lo Hueco – Spanish for “The Hollow” – in mountainous south-central Spain. The fossils were discovered during work to install rails for a high-speed train between Madrid and Valencia.

Among the discoveries were partial skeletons of sauropods, a group of long-necked plant-eating dinosaurs that includes titanosaurs. Titanosaurs were the largest animals to ever live. This is a rare find in Europe. Scientists are still studying the fossils. And they think there could be more new species awaiting discovery at Lo Hueco.

Q. pintiquiniestra is a notable find from this fossil collection. And that’s because many bones from an individual dinosaur were recovered and pieced together, including backbones and ribs, as well as part of the pelvis, tail and legs. As a result, scientists were able to identify it as a new dinosaur species due to the unique features of its bones.

Qunkasaura pintiquiniestra fossils on display at the Paleontological Museum of Castilla-La Mancha in Spain. Image via GBE-UNED.

Discoveries are a revelation about European dinosaur evolution

Pedro Mocho, of the University of Lisbon, is the lead author of the paper. In an interview, he told ABC News that he thinks that this individual was a sub-adult based on the appearance of the dinosaur’s vertebrae. He also mentioned that the dinosaur’s tail had features similar to titanosaurs found in South America.

In a statement, Mocho said this finding is significant because it reveals the presence of two types of saltasauroids in the same fossil bed. Saltasauroids are a type of titanosaur with a smaller body size compared to their larger relatives. This new discovery is helping scientists better understand the diversity of these dinosaurs during the Cretaceous in Europe.

Mocho said in the statement:

The study of this specimen allowed us to identify for the first time the presence of two distinct lineages of saltasauroids in the same fossil locality.

One of these groups, called Lirainosaurinae, is relatively known in the Iberian region and is characterized by small and medium-sized species, which evolved in an island ecosystem. In other words, Europe was a huge archipelago made up of several islands during the Late Cretaceous.

However, Qunkasaura belongs to another group of sauropods, represented in the Iberian Peninsula by medium-large species 73 million years ago. This suggests to us that this lineage arrived in the Iberian Peninsula much later than other groups of dinosaurs.

How Qunkasaura got its tongue-twisting name

The name Qunkasaura pintiquiniestra derives from several sources. “Qunka” is a name once used for a city near the area where the fossils were found. “Saura” is a form of the Greek word for lizard. In addition, “saura” also recognizes Spanish painter Antonio Saura. “Pintiquiniestra” refers to a character from the novel Don Quixote by Miguel de Cervantes.

Excavation of Qunkasaura pintiquiniestra at the Lo Hueco site in 2007. Image via GBE-UNED.

Bottom line: A new species of titanosaur, a large plant-eating dinosaur with a long neck, was discovered near Cuenca, Spain. It lived 73 million years ago.

Source: A Spanish saltasauroid titanosaur reveals Europe as a melting pot of endemic and immigrant sauropods in the Late Cretaceous

Via Eurekalert (English version)

Via University of Lisbon (Original Portugese press release)

Read more: Eggshells support idea that dinosaurs were warm-blooded

The post New dinosaur – a long-necked titanosaur – uncovered in Spain first appeared on EarthSky.

from EarthSky https://ift.tt/EyctLeQ

Artist’s concept of the dinosaur Qunkasaura pintiquiniestra. Image via José Antonio Peñas Artero / University of Lisbon.

A new species of titanosaur – Qunkasaura pintiquiniestra – was discovered near Cuenca, Spain. It lived around 73 million years ago.

The animal’s well-preserved partial skeleton allowed scientists to identify it as a new species.

Two distinct groups of smaller titanosaurs called saltasauroids were found at the site, adding more diversity to the list of dinosaurs roaming Europe during the Cretaceous.

Meet Q. pintiquiniestra, an enormous vegetarian dinosaur from ancient Spain

A new species of titanosaur – a variety of large long-necked plant-eating dinosaur – was recently recovered from a fossil bed near Cuenca, Spain. The newly identified animals lived around 73 million years ago, during the late Cretaceous Period.

Scientists who identified the oversize dino announced their discovery this week in the journal Communications Biology. Their findings were published on September 4, 2024.

And its name is a mouthful. The group called the dinosaur Qunkasaura pintiquiniestra.

A treasure trove of dinosaur fossils unearthed in Spain

In 2007, thousands of fossils were collected at a site called Lo Hueco – Spanish for “The Hollow” – in mountainous south-central Spain. The fossils were discovered during work to install rails for a high-speed train between Madrid and Valencia.

Among the discoveries were partial skeletons of sauropods, a group of long-necked plant-eating dinosaurs that includes titanosaurs. Titanosaurs were the largest animals to ever live. This is a rare find in Europe. Scientists are still studying the fossils. And they think there could be more new species awaiting discovery at Lo Hueco.

Q. pintiquiniestra is a notable find from this fossil collection. And that’s because many bones from an individual dinosaur were recovered and pieced together, including backbones and ribs, as well as part of the pelvis, tail and legs. As a result, scientists were able to identify it as a new dinosaur species due to the unique features of its bones.

Qunkasaura pintiquiniestra fossils on display at the Paleontological Museum of Castilla-La Mancha in Spain. Image via GBE-UNED.

Discoveries are a revelation about European dinosaur evolution

Pedro Mocho, of the University of Lisbon, is the lead author of the paper. In an interview, he told ABC News that he thinks that this individual was a sub-adult based on the appearance of the dinosaur’s vertebrae. He also mentioned that the dinosaur’s tail had features similar to titanosaurs found in South America.

In a statement, Mocho said this finding is significant because it reveals the presence of two types of saltasauroids in the same fossil bed. Saltasauroids are a type of titanosaur with a smaller body size compared to their larger relatives. This new discovery is helping scientists better understand the diversity of these dinosaurs during the Cretaceous in Europe.

Mocho said in the statement:

The study of this specimen allowed us to identify for the first time the presence of two distinct lineages of saltasauroids in the same fossil locality.

One of these groups, called Lirainosaurinae, is relatively known in the Iberian region and is characterized by small and medium-sized species, which evolved in an island ecosystem. In other words, Europe was a huge archipelago made up of several islands during the Late Cretaceous.

However, Qunkasaura belongs to another group of sauropods, represented in the Iberian Peninsula by medium-large species 73 million years ago. This suggests to us that this lineage arrived in the Iberian Peninsula much later than other groups of dinosaurs.

How Qunkasaura got its tongue-twisting name

The name Qunkasaura pintiquiniestra derives from several sources. “Qunka” is a name once used for a city near the area where the fossils were found. “Saura” is a form of the Greek word for lizard. In addition, “saura” also recognizes Spanish painter Antonio Saura. “Pintiquiniestra” refers to a character from the novel Don Quixote by Miguel de Cervantes.

Excavation of Qunkasaura pintiquiniestra at the Lo Hueco site in 2007. Image via GBE-UNED.

Bottom line: A new species of titanosaur, a large plant-eating dinosaur with a long neck, was discovered near Cuenca, Spain. It lived 73 million years ago.

Source: A Spanish saltasauroid titanosaur reveals Europe as a melting pot of endemic and immigrant sauropods in the Late Cretaceous

Via Eurekalert (English version)

Via University of Lisbon (Original Portugese press release)

Read more: Eggshells support idea that dinosaurs were warm-blooded

The post New dinosaur – a long-necked titanosaur – uncovered in Spain first appeared on EarthSky.

from EarthSky https://ift.tt/EyctLeQ

A buddy for Betelgeuse? Does this mean no supernova?

The red supergiant star Betelgeuse is a beloved star, bright and easy to see in the famous constellation Orion the Hunter. See the “bump” on the left side in this submillimeter-wavelength image of the star? It’s hot gas from the red giant star’s extended atmosphere. Image via the ALMA telescope in Chile in 2020/ ESO/ NAOJ/NRAO)/ E. O’Gorman/ P. Kervella.

• Betelgeuse might not be one star, but two! The smaller star could be 1.7 times the mass of our sun.
• Betelgeuse underwent a “great dimming” in recent years, causing some astronomers to think it might be on the verge of exploding as a supernova. But now a team of astronomers thinks the smaller star plays a role in Betelgeuse’s variability.
• If Betelgeuse has a companion, it might mean this star – the nearest red supergiant to Earth at 427 light-years – won’t go supernova for a long time.

Betelgeuse might have a buddy

A close analysis of the light curve – the record of starlight waxing and waning – for the old red supergiant star Betelgeuse has revealed the possibility of a 2nd star in the system. In other words, the single point of light we see as Betelgeuse might be 2 stars, with the smaller one about 1.7 times the mass of our sun. If this is so … is the explosion of Betelgeuse as a supernova still about to happen?

Betelgeuse is a variable star. It periodically changes in brightness and sometimes has irregular light changes. In recent years, it has undergone periods of dimming, which have caused astronomers to speculate that Betelgeuese – which is the nearest red supergiant to Earth at 427 light-years away – might be on the verge of going supernova.

Prior to the Great Dimming of Betelgeuse in 2019, astronomers said that, yes, Betelgeuse was due to explode, but perhaps not for thousands of years.

Here’s the famous constellation Orion the Hunter in the night sky. You’ll find it high in the east on September mornings. It’s easily recognizable for its 3 Belt stars, 3 medium-bright stars in a short, straight row. Betelgeuse is one of Orion’s 2 brightest stars. It is distinctly red in color and shines with a somber light.

The out-of-sync variation of Betelgeuse

A trio of astronomers investigated a 2,170-day cycle of dimming and brightening of Betelgeuse. These scientists describe a long secondary period of variation, which isn’t unusual for stars of Betelgeuse’s class. However, the most common explanation for long secondary periods tends to be that the stars are in binary systems. And, they say, this explanation is specifically likely at Betelgeuse.

Variable stars like Betelgeuse pulse. They literally grow larger and smaller over time. We can study the variability of Betelgeuse in part via a a technique called radial velocity, the movement of something in space (in this case, the movement of the outer surface of Betelgeuse) toward or away from us. But, at Betelgeuse, the radial velocity variation doesn’t line up with the star’s light curve, the measurement of its waxing and waning in brightness. It’s like someone clapping on exactly the wrong beat.

Authors of the paper – astronomers Jared A. Goldberg, Meridith Joyce and László Molnár – claim this out-of-syncness is a smoking gun. Betelgeuse, they said, isn’t alone:

The light curve-radial velocity phase difference requires a companion to be behind Betelgeuse at the long secondary period luminosity minimum …

In other words, they said, Betelgeuse is brightest when the red supergiant star and its hypothetical little buddy are shining together, as seen from our earthly perspective.

This new work resulted in a study that was submitted August 17, 2024, to the online scholarly archive arXiv.

This schematic shows the dust modulation by a companion star of Betelgeuse over the course of one orbit. The diagram in the center shows 4 orientations of the companion (black circle) as well as Betelgeuse (solid red blob) and some circumstellar gas and dust (curly lines). The arrows represent the motion of the 2 objects. Read more about this image via arXiv.

The Great Dimming and its aftermath

Back in 2019, Betelgeuse’s brightness dropped dramatically and unexpectedly. The turning down of the lights lasted until 2020. Later, that time of dimming for Betelgeuse became known as the Great Dimming. There was much speculation that Betelgeuse might be about to explode! But it didn’t explode, and, later, dust was offered as an explanation for the dimming.

Yet the Great Dimming trigged a wave of interest in Betelgeuse. It caught people’s imaginations: would we see this familiar red star blaze forth in brightness, becoming the brightest star in our night sky, perhaps even visible in the daytime?

That’s why the authors of the new paper describe their results about Betelgeuse as groundbreaking:

These studies have led to revisions in our understanding of Betelgeuse’s behavior and fundamental parameters, as well as opened new lines of inquiry into some of Betelgeuse’s less well-understood properties …

So is Betelgeuse a binary? The notion Betelgeuse is a binary star dates back at least 25 years. But observations and interpretations since the Great Dimming dust storm strongly reinforce the idea. And the authors say dust is important to understanding what’s going on:

While such early versions of the binarity hypothesis were most concerned with whether a close companion could induce low-frequency modes on the primary star, the current leading theory is that the timescale of the LSP period is set by the orbital time of a low-mass companion, and the mechanism of dimming and brightening involves the formation and removal of dust along the line of sight in phase with the companion’s orbit.

Supernova soon? Not if it’s a binary star

Knowing if another, smaller star lurks off the shoulder of Orion may tell us how long Betelgeuse has to live. Betelgeuse is still expected one day – maybe soon, maybe in thousands of years – to explode as a supernova.

When it blows depends on whether a companion star is making it move.

Betelgeuse has another well-known periodicity in its orbit. This one fluctuates on a cycle of about 420 days, and is believed to be the star’s fundamental mode. If it isn’t, Betelgeuse will go supernova sooner than later.

The paper explains:

If the 2,100-day periodicity is the fundamental mode, it implies a large and observationally contentious radius for Betelgeuse. Further, it would place Betelgeuse’s current evolutionary stage beyond the onset of core carbon burning, suggesting that a supernova explosion is imminent within the next several dozen to several hundred years. If, on the other hand, the 2,100-day periodicity is an LSP, Betelgeuse is comfortably within in its core helium burning phase and not due for an explosion for hundreds of thousands of years.

This means things don’t look good for those hoping to see a nearby supernova in their lifetimes. The trio of authors say their data means Betelgeuse probably isn’t alone:

We overview all of the scenarios proposed as an explanation for Betelgeuse’s LSP, demonstrating critical flaws in all but one case: Betelgeuse has a companion that interacts with the star’s dusty circumstellar environment.

Not in our lifetime

When Betelgeuse finally blows, it’ll probably be visible in the daytime. But that might not be for at least hundreds of thousands of years, according to the ideas presented in this new research.

No supernova in the offing? Artist’s concept of the old red supergiant star Betelgeuse as a supernova, or exploding star. Stars like Betelgeuse are thought to dim dramatically before they explode. But if a component of Betelgeuse’s variability is caused by a companion star, its supernova explosion may be far in the future. Image via Royal Astronomical Society/ ESO/ L. Calçada (CC BY 4.0).

Bottom line: A recently published study suggests the red giant star Betelgeuse might have a sun-size companion. Betelgeuse’s buddy would explain some of the intricacies in astronomers’ measurements of the star’s brightness and variability.

Read more: Betelgeuse: The Great Dimming of 2019-2020

Source: A Buddy for Betelgeuse: Binarity as the Origin of the Long Secondary Period in b Orionis

The post A buddy for Betelgeuse? Does this mean no supernova? first appeared on EarthSky.

from EarthSky https://ift.tt/tv5HGTQ

The red supergiant star Betelgeuse is a beloved star, bright and easy to see in the famous constellation Orion the Hunter. See the “bump” on the left side in this submillimeter-wavelength image of the star? It’s hot gas from the red giant star’s extended atmosphere. Image via the ALMA telescope in Chile in 2020/ ESO/ NAOJ/NRAO)/ E. O’Gorman/ P. Kervella.

• Betelgeuse might not be one star, but two! The smaller star could be 1.7 times the mass of our sun.
• Betelgeuse underwent a “great dimming” in recent years, causing some astronomers to think it might be on the verge of exploding as a supernova. But now a team of astronomers thinks the smaller star plays a role in Betelgeuse’s variability.
• If Betelgeuse has a companion, it might mean this star – the nearest red supergiant to Earth at 427 light-years – won’t go supernova for a long time.

Betelgeuse might have a buddy

A close analysis of the light curve – the record of starlight waxing and waning – for the old red supergiant star Betelgeuse has revealed the possibility of a 2nd star in the system. In other words, the single point of light we see as Betelgeuse might be 2 stars, with the smaller one about 1.7 times the mass of our sun. If this is so … is the explosion of Betelgeuse as a supernova still about to happen?

Betelgeuse is a variable star. It periodically changes in brightness and sometimes has irregular light changes. In recent years, it has undergone periods of dimming, which have caused astronomers to speculate that Betelgeuese – which is the nearest red supergiant to Earth at 427 light-years away – might be on the verge of going supernova.

Prior to the Great Dimming of Betelgeuse in 2019, astronomers said that, yes, Betelgeuse was due to explode, but perhaps not for thousands of years.

Here’s the famous constellation Orion the Hunter in the night sky. You’ll find it high in the east on September mornings. It’s easily recognizable for its 3 Belt stars, 3 medium-bright stars in a short, straight row. Betelgeuse is one of Orion’s 2 brightest stars. It is distinctly red in color and shines with a somber light.

The out-of-sync variation of Betelgeuse

A trio of astronomers investigated a 2,170-day cycle of dimming and brightening of Betelgeuse. These scientists describe a long secondary period of variation, which isn’t unusual for stars of Betelgeuse’s class. However, the most common explanation for long secondary periods tends to be that the stars are in binary systems. And, they say, this explanation is specifically likely at Betelgeuse.

Variable stars like Betelgeuse pulse. They literally grow larger and smaller over time. We can study the variability of Betelgeuse in part via a a technique called radial velocity, the movement of something in space (in this case, the movement of the outer surface of Betelgeuse) toward or away from us. But, at Betelgeuse, the radial velocity variation doesn’t line up with the star’s light curve, the measurement of its waxing and waning in brightness. It’s like someone clapping on exactly the wrong beat.

Authors of the paper – astronomers Jared A. Goldberg, Meridith Joyce and László Molnár – claim this out-of-syncness is a smoking gun. Betelgeuse, they said, isn’t alone:

The light curve-radial velocity phase difference requires a companion to be behind Betelgeuse at the long secondary period luminosity minimum …

In other words, they said, Betelgeuse is brightest when the red supergiant star and its hypothetical little buddy are shining together, as seen from our earthly perspective.

This new work resulted in a study that was submitted August 17, 2024, to the online scholarly archive arXiv.

This schematic shows the dust modulation by a companion star of Betelgeuse over the course of one orbit. The diagram in the center shows 4 orientations of the companion (black circle) as well as Betelgeuse (solid red blob) and some circumstellar gas and dust (curly lines). The arrows represent the motion of the 2 objects. Read more about this image via arXiv.

The Great Dimming and its aftermath

Back in 2019, Betelgeuse’s brightness dropped dramatically and unexpectedly. The turning down of the lights lasted until 2020. Later, that time of dimming for Betelgeuse became known as the Great Dimming. There was much speculation that Betelgeuse might be about to explode! But it didn’t explode, and, later, dust was offered as an explanation for the dimming.

Yet the Great Dimming trigged a wave of interest in Betelgeuse. It caught people’s imaginations: would we see this familiar red star blaze forth in brightness, becoming the brightest star in our night sky, perhaps even visible in the daytime?

That’s why the authors of the new paper describe their results about Betelgeuse as groundbreaking:

These studies have led to revisions in our understanding of Betelgeuse’s behavior and fundamental parameters, as well as opened new lines of inquiry into some of Betelgeuse’s less well-understood properties …

So is Betelgeuse a binary? The notion Betelgeuse is a binary star dates back at least 25 years. But observations and interpretations since the Great Dimming dust storm strongly reinforce the idea. And the authors say dust is important to understanding what’s going on:

While such early versions of the binarity hypothesis were most concerned with whether a close companion could induce low-frequency modes on the primary star, the current leading theory is that the timescale of the LSP period is set by the orbital time of a low-mass companion, and the mechanism of dimming and brightening involves the formation and removal of dust along the line of sight in phase with the companion’s orbit.

Supernova soon? Not if it’s a binary star

Knowing if another, smaller star lurks off the shoulder of Orion may tell us how long Betelgeuse has to live. Betelgeuse is still expected one day – maybe soon, maybe in thousands of years – to explode as a supernova.

When it blows depends on whether a companion star is making it move.

Betelgeuse has another well-known periodicity in its orbit. This one fluctuates on a cycle of about 420 days, and is believed to be the star’s fundamental mode. If it isn’t, Betelgeuse will go supernova sooner than later.

The paper explains:

If the 2,100-day periodicity is the fundamental mode, it implies a large and observationally contentious radius for Betelgeuse. Further, it would place Betelgeuse’s current evolutionary stage beyond the onset of core carbon burning, suggesting that a supernova explosion is imminent within the next several dozen to several hundred years. If, on the other hand, the 2,100-day periodicity is an LSP, Betelgeuse is comfortably within in its core helium burning phase and not due for an explosion for hundreds of thousands of years.

This means things don’t look good for those hoping to see a nearby supernova in their lifetimes. The trio of authors say their data means Betelgeuse probably isn’t alone:

We overview all of the scenarios proposed as an explanation for Betelgeuse’s LSP, demonstrating critical flaws in all but one case: Betelgeuse has a companion that interacts with the star’s dusty circumstellar environment.

Not in our lifetime

When Betelgeuse finally blows, it’ll probably be visible in the daytime. But that might not be for at least hundreds of thousands of years, according to the ideas presented in this new research.

No supernova in the offing? Artist’s concept of the old red supergiant star Betelgeuse as a supernova, or exploding star. Stars like Betelgeuse are thought to dim dramatically before they explode. But if a component of Betelgeuse’s variability is caused by a companion star, its supernova explosion may be far in the future. Image via Royal Astronomical Society/ ESO/ L. Calçada (CC BY 4.0).

Bottom line: A recently published study suggests the red giant star Betelgeuse might have a sun-size companion. Betelgeuse’s buddy would explain some of the intricacies in astronomers’ measurements of the star’s brightness and variability.

Read more: Betelgeuse: The Great Dimming of 2019-2020

Source: A Buddy for Betelgeuse: Binarity as the Origin of the Long Secondary Period in b Orionis

The post A buddy for Betelgeuse? Does this mean no supernova? first appeared on EarthSky.

from EarthSky https://ift.tt/tv5HGTQ

Great Square of Pegasus gallops into the autumn sky

Great Square of Pegasus

Look east just after dark for the Great Square of Pegasus around the time of the September equinox (in 2024, it will be on September 22). Throughout late September and October evenings, the Great Square will be ascending in the eastern evening sky. The Great Square consists of four stars of nearly equal brightness. Specifically, they are Scheat, Alpheratz, Markab and Algenib. Incidentally, the constellation Pegasus represents a Flying Horse. But the Great Square – a prominent asterism within Pegasus – is a landmark of the Northern Hemisphere’s autumn sky.

The Great Square of Pegasus consists of 4 stars of nearly equal brightness: Scheat, Alpheratz, Markab and Algenib. The Great Square is an asterism within the constellation Pegasus.

To find the Great Square

First of all, to find the Great Square, use the Big Dipper to star-hop to Polaris, the North Star. Then draw an imaginary line from Polaris until you land an outer star on the W or M-shaped constellation Cassiopeia the Queen.

Finally, a line from Cassiopeia faithfully escorts you to the Great Square of Pegasus.

Use the two stars at the end of the bowl in the Big Dipper to find Polaris. Then use Polaris to find Cassiopeia. From there you can find the Great Square of Pegasus. Chart via Stellarium. Used with permission. Animation by EarthSky.

Great Square is an asterism, not a constellation

Like the Big Dipper, the Great Square of Pegasus isn’t a constellation. Instead, it’s an asterism, or noticeable pattern on our sky’s dome. And, like the Big Dipper, the Great Square can be used to help you find other sky treasures, the most notable being the Andromeda galaxy, another famous sight on autumn evenings in the Northern Hemisphere.

Read more: 2 ways to find the Andromeda galaxy

As you can see, the Great Square of Pegasus can help guide you to the Andromeda galaxy. Here’s how to do it.

Great Square of Pegasus: A big square of nothing

Often, at events where many are stargazing for the first time, one may hear:

… the Great Square has nothing in it.

But, of course, the Great Square isn’t empty. In fact, no part of the night sky is really empty. But because the stars inside the Great Square are so faint, the unaided eye can’t easily detect them. However, if you use binoculars or a small telescope you can see many stars within the Great Square. Counting stars inside the Great Square is a good way to determine how dark your sky is when observing.

First discovery of an exoplanet orbiting a sun-like star

One of the most famous faint stars near the Great Square is 51 Pegasi. In 1995, astronomers announced in the journal Nature they’d discovered a planet around this star, and it is now called 51 Pegasi b. After a few months of skepticism from the astronomical community, it was confirmed that the first planet beyond our solar system had been discovered.

Now we know that at least 12 stars in Pegasus have exoplanets, and astronomers have confirmed more than 5,700 exoplanets in our Milky Way galaxy. The astronomers who found 51 Pegasi b – Michel Mayor of the University of Geneva and Didier Queloz at the Cavendish Laboratory and Geneva University – received the 2019 Nobel Prize in Physics for their discovery.

Some books say that 51 Pegasi is visible with the unaided eye alone. But it’s a challenge. Using binoculars, look roughly halfway between Scheat and Markab in the Great Square of Pegasus. Note that you won’t be able to see the planets. Pegasus 51 is approximately 50 light-years away from Earth.

Learn the stars of Pegasus and where to find its deep-sky targets. Look near the center for 51 Pegasi. Chart via EarthSky.

Mythology of the Great Square of Pegasus

You might recall that Pegasus was a winged horse in Greek mythology. The constellation Pegasus is one of seven constellations in the autumn sky that explain why it’s never a good idea to claim a mortal’s beauty is greater than that of the gods. You’ll find this story plastered all over the autumn night sky, and Pegasus figures into it prominently.

The story goes that Cassiopeia the Queen bragged that she (or her daughter Andromeda the Princess) was more beautiful than the immortal Nereids, or sea nymphs. This angered the gods, who asked the sea-god Poseidon to take revenge. The punishment was that Cepheus the King and Cassiopeia had to sacrifice Andromeda to Cetus the Whale (sometimes called a sea monster). Andromeda was chained to a rock at sea. She was about to be gobbled up by Cetus, when she saw Perseus the Hero – riding Pegasus the Flying Horse – swooping toward her.

Perseus had a trick up his sleeve. He faced Cetus, holding up the head of the Gorgon Medusa. It’s said the sight of the Medusa turned Cetus to stone. Then Perseus whacked the chains that bound Andromeda and freed her. And then, they rode off on Pegasus the Flying Horse and lived happily ever after. Later, Zeus placed all of them in the sky as stars, along with Delphinus the Dolphin, who’d provided comfort to Andromeda.

The Great Square of Pegasus makes up the eastern (left) half of the constellation Pegasus. Image via International Astronomical Union. Used with permission.

Bottom line: How you can see the Great Square of Pegasus star pattern.

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The post Great Square of Pegasus gallops into the autumn sky first appeared on EarthSky.

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Great Square of Pegasus

Look east just after dark for the Great Square of Pegasus around the time of the September equinox (in 2024, it will be on September 22). Throughout late September and October evenings, the Great Square will be ascending in the eastern evening sky. The Great Square consists of four stars of nearly equal brightness. Specifically, they are Scheat, Alpheratz, Markab and Algenib. Incidentally, the constellation Pegasus represents a Flying Horse. But the Great Square – a prominent asterism within Pegasus – is a landmark of the Northern Hemisphere’s autumn sky.

The Great Square of Pegasus consists of 4 stars of nearly equal brightness: Scheat, Alpheratz, Markab and Algenib. The Great Square is an asterism within the constellation Pegasus.

To find the Great Square

First of all, to find the Great Square, use the Big Dipper to star-hop to Polaris, the North Star. Then draw an imaginary line from Polaris until you land an outer star on the W or M-shaped constellation Cassiopeia the Queen.

Finally, a line from Cassiopeia faithfully escorts you to the Great Square of Pegasus.

Use the two stars at the end of the bowl in the Big Dipper to find Polaris. Then use Polaris to find Cassiopeia. From there you can find the Great Square of Pegasus. Chart via Stellarium. Used with permission. Animation by EarthSky.

Great Square is an asterism, not a constellation

Like the Big Dipper, the Great Square of Pegasus isn’t a constellation. Instead, it’s an asterism, or noticeable pattern on our sky’s dome. And, like the Big Dipper, the Great Square can be used to help you find other sky treasures, the most notable being the Andromeda galaxy, another famous sight on autumn evenings in the Northern Hemisphere.

Read more: 2 ways to find the Andromeda galaxy

As you can see, the Great Square of Pegasus can help guide you to the Andromeda galaxy. Here’s how to do it.

Great Square of Pegasus: A big square of nothing

Often, at events where many are stargazing for the first time, one may hear:

… the Great Square has nothing in it.

But, of course, the Great Square isn’t empty. In fact, no part of the night sky is really empty. But because the stars inside the Great Square are so faint, the unaided eye can’t easily detect them. However, if you use binoculars or a small telescope you can see many stars within the Great Square. Counting stars inside the Great Square is a good way to determine how dark your sky is when observing.

First discovery of an exoplanet orbiting a sun-like star

One of the most famous faint stars near the Great Square is 51 Pegasi. In 1995, astronomers announced in the journal Nature they’d discovered a planet around this star, and it is now called 51 Pegasi b. After a few months of skepticism from the astronomical community, it was confirmed that the first planet beyond our solar system had been discovered.

Now we know that at least 12 stars in Pegasus have exoplanets, and astronomers have confirmed more than 5,700 exoplanets in our Milky Way galaxy. The astronomers who found 51 Pegasi b – Michel Mayor of the University of Geneva and Didier Queloz at the Cavendish Laboratory and Geneva University – received the 2019 Nobel Prize in Physics for their discovery.

Some books say that 51 Pegasi is visible with the unaided eye alone. But it’s a challenge. Using binoculars, look roughly halfway between Scheat and Markab in the Great Square of Pegasus. Note that you won’t be able to see the planets. Pegasus 51 is approximately 50 light-years away from Earth.

Learn the stars of Pegasus and where to find its deep-sky targets. Look near the center for 51 Pegasi. Chart via EarthSky.

Mythology of the Great Square of Pegasus

You might recall that Pegasus was a winged horse in Greek mythology. The constellation Pegasus is one of seven constellations in the autumn sky that explain why it’s never a good idea to claim a mortal’s beauty is greater than that of the gods. You’ll find this story plastered all over the autumn night sky, and Pegasus figures into it prominently.

The story goes that Cassiopeia the Queen bragged that she (or her daughter Andromeda the Princess) was more beautiful than the immortal Nereids, or sea nymphs. This angered the gods, who asked the sea-god Poseidon to take revenge. The punishment was that Cepheus the King and Cassiopeia had to sacrifice Andromeda to Cetus the Whale (sometimes called a sea monster). Andromeda was chained to a rock at sea. She was about to be gobbled up by Cetus, when she saw Perseus the Hero – riding Pegasus the Flying Horse – swooping toward her.

Perseus had a trick up his sleeve. He faced Cetus, holding up the head of the Gorgon Medusa. It’s said the sight of the Medusa turned Cetus to stone. Then Perseus whacked the chains that bound Andromeda and freed her. And then, they rode off on Pegasus the Flying Horse and lived happily ever after. Later, Zeus placed all of them in the sky as stars, along with Delphinus the Dolphin, who’d provided comfort to Andromeda.

The Great Square of Pegasus makes up the eastern (left) half of the constellation Pegasus. Image via International Astronomical Union. Used with permission.

Bottom line: How you can see the Great Square of Pegasus star pattern.

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

The post Great Square of Pegasus gallops into the autumn sky first appeared on EarthSky.

from EarthSky https://ift.tt/ipkS5Mx