How the galaxy’s ejected object was found<\/strong><\/h2>Citizen scientists<\/a> play a key role in assisting astronomical studies of the Universe and in space missions.<\/p>These volunteers give their time to a range of projects, from helping discover exoplanets<\/a> to producing colour images out of raw data captured by space probes<\/a>.<\/p>In this case, citizen scientists were working on NASA\u2019s Backyard Worlds: Planet 9<\/a> project, which uses images from NASA\u2019s WISE (Wide Field Infrared Explorer) mission.<\/p>WISE mapped the sky in infrared<\/a> light from 2009 to 2011 and was then re-activated as NEOWISE (Near-Earth Object Wide-field Infrared Survey Explorer) in 2013, before being retired on 8 August 2024.<\/p>Citizen scientists Martin Kabatnik, Thomas P. Bickle and Dan Caselden found a faint object called CWISE J124909.08+362116.0 zipping across the galaxy while checking WISE images.<\/p>
Follow-up observations were made with ground-based telescopes, enabling astronomers to confirm that they were seeing what they thought they were seeing, and to characterise the object.<\/p>
They found that CWISE J1249 is speeding out of the Milky Way at 1 million miles per hour.<\/p>![\"Artist's](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/08\/nasa-neowise-1024x576.jpg?fit=800%2C450\")
Artist’s impression of the NEOWISE spacecraft. Credit: NASA\/JPL-Caltech<\/figcaption><\/figure>What is CWISE J1249?<\/strong><\/h2>It has a low mass, making it difficult to classify: it could be a low-mass star or a brown dwarf (an object that’s categorised between a gas giant planet and a star).<\/p>
The citizen scientists are co-authors of a study that’s been published in the Astrophysical Journal Letters.<\/p>
“I can\u2019t describe the level of excitement,” says Kabatnik, a citizen scientist from Nuremberg, Germany.<\/p>
“When I first saw how fast it was moving, I was convinced it must have been reported already.”<\/p>
If it is a brown dwarf, it joins some over 4,000 that have been discovered by Backyard Worlds: Planet 9 volunteers.<\/p>
However, CWISE J1249 is the only one discovered so far to be speeding its way out of the galaxy.<\/p>
Observations using the famous W. M. Keck Observatory in Maunakea, Hawaii, reveal it has much less iron and other metals than other stars and brown dwarfs.<\/p>
That, say astronomers, means it’s likely extremely old: even from the first generations of stars in our galaxy.<\/p>![\"CWISE](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/08\/CWISE-J1249-1024x536.jpg?fit=800%2C419\")
CWISE J1249 may be a brown dwarf ejected from a binary system following the explosion of its white dwarf companion. Credit: W.M. Keck Observatory\/Adam Makarenko<\/figcaption><\/figure>Why is CWISE J1249 moving so fast?<\/strong><\/h2>Why has CWISE J1249 been ejected out of the Milky Way at 1 million miles per hour?<\/p>
Astronomers suggest it may have originally been part of a binary system<\/a> with a white dwarf<\/a>, which exploded as a supernova<\/a> when it accreted too much material from its companion. <\/p>Or it may have been part of a type of ancient star cluster known as a globular cluster<\/a>, and a close encounter with a pair of black holes<\/a> boosted it out of the galaxy.<\/p>“When a star encounters a black hole binary, the complex dynamics of this three-body interaction<\/a> can toss that star right out of the globular cluster,” says Kyle Kremer, incoming assistant professor in UC San Diego\u2019s Department of Astronomy and Astrophysics.<\/p>Scientists are now going to gather more data on CWISE J1249 to attempt to discern which of these scenarios is most likely.<\/p>
The study is led by Backyard Worlds: Planet 9 science team member Adam Burgasser, a professor at the University of California, San Diego, and includes co-authors Hunter Brooks and Austin Rothermich, astronomy students who both began their astronomy careers as citizen scientists.<\/p>
These volunteers give their time to a range of projects, from helping discover exoplanets<\/a> to producing colour images out of raw data captured by space probes<\/a>.<\/p> In this case, citizen scientists were working on NASA\u2019s Backyard Worlds: Planet 9<\/a> project, which uses images from NASA\u2019s WISE (Wide Field Infrared Explorer) mission.<\/p> WISE mapped the sky in infrared<\/a> light from 2009 to 2011 and was then re-activated as NEOWISE (Near-Earth Object Wide-field Infrared Survey Explorer) in 2013, before being retired on 8 August 2024.<\/p> Citizen scientists Martin Kabatnik, Thomas P. Bickle and Dan Caselden found a faint object called CWISE J124909.08+362116.0 zipping across the galaxy while checking WISE images.<\/p> Follow-up observations were made with ground-based telescopes, enabling astronomers to confirm that they were seeing what they thought they were seeing, and to characterise the object.<\/p> They found that CWISE J1249 is speeding out of the Milky Way at 1 million miles per hour.<\/p> It has a low mass, making it difficult to classify: it could be a low-mass star or a brown dwarf (an object that’s categorised between a gas giant planet and a star).<\/p> The citizen scientists are co-authors of a study that’s been published in the Astrophysical Journal Letters.<\/p> “I can\u2019t describe the level of excitement,” says Kabatnik, a citizen scientist from Nuremberg, Germany.<\/p> “When I first saw how fast it was moving, I was convinced it must have been reported already.”<\/p> If it is a brown dwarf, it joins some over 4,000 that have been discovered by Backyard Worlds: Planet 9 volunteers.<\/p> However, CWISE J1249 is the only one discovered so far to be speeding its way out of the galaxy.<\/p> Observations using the famous W. M. Keck Observatory in Maunakea, Hawaii, reveal it has much less iron and other metals than other stars and brown dwarfs.<\/p> That, say astronomers, means it’s likely extremely old: even from the first generations of stars in our galaxy.<\/p> Why has CWISE J1249 been ejected out of the Milky Way at 1 million miles per hour?<\/p> Astronomers suggest it may have originally been part of a binary system<\/a> with a white dwarf<\/a>, which exploded as a supernova<\/a> when it accreted too much material from its companion. <\/p> Or it may have been part of a type of ancient star cluster known as a globular cluster<\/a>, and a close encounter with a pair of black holes<\/a> boosted it out of the galaxy.<\/p> “When a star encounters a black hole binary, the complex dynamics of this three-body interaction<\/a> can toss that star right out of the globular cluster,” says Kyle Kremer, incoming assistant professor in UC San Diego\u2019s Department of Astronomy and Astrophysics.<\/p> Scientists are now going to gather more data on CWISE J1249 to attempt to discern which of these scenarios is most likely.<\/p> The study is led by Backyard Worlds: Planet 9 science team member Adam Burgasser, a professor at the University of California, San Diego, and includes co-authors Hunter Brooks and Austin Rothermich, astronomy students who both began their astronomy careers as citizen scientists.<\/p>What is CWISE J1249?<\/strong><\/h2>
Why is CWISE J1249 moving so fast?<\/strong><\/h2>