Citizen scientists collaborating with NASA's Backyard Worlds project have made a groundbreaking discovery: a unique hypervelocity object, CWISE J1249, that is rapidly escaping the Milky Way. This object is the first of its kind with a mass similar to or less than a small star.
Leveraging infrared images from NASA's WISE mission, amateur astronomers identified the object's unusual speed and composition. CWISE J1249 is likely a low-mass star or brown dwarf with an ancient origin. Its high velocity is theorized to be the result of interactions with supernovae or black holes, suggesting a dramatic past within the cosmos.
A Citizen Science Triumph
Backyard Worlds, a citizen science project, utilizes images from NASA's WISE mission to map the sky in infrared light. A few years ago, dedicated volunteers Martin Kabatnik, Thomas P. Bickle, and Dan Caselden spotted a faint, fast-moving object in the WISE data. Subsequent observations confirmed the discovery and characterized the object.
"I was convinced it must have been reported already," said Kabatnik, a citizen scientist from Nuremberg, Germany, expressing his excitement at the discovery.
Unraveling the Mystery of CWISE J1249
CWISE J1249 is hurtling out of the Milky Way at approximately 1 million miles per hour. Its low mass makes it difficult to classify as either a star or a brown dwarf. While brown dwarfs are not uncommon, CWISE J1249's high velocity and unique composition set it apart.
Analysis of the object's elemental composition reveals that it has significantly less iron and other metals than typical stars and brown dwarfs. This suggests an ancient origin, placing it among the first generations of stars in our galaxy.
Theories Behind the High-Speed Escape
Scientists propose two potential scenarios for CWISE J1249's high velocity. One hypothesis involves a binary system with a white dwarf that exploded as a supernova, propelling the object into space. Alternatively, a chance encounter with a pair of black holes in a globular cluster could have accelerated it to its current speed.
Further studies of CWISE J1249's elemental composition will help determine which of these scenarios is most likely.
Source:
Published 8 August 2024, The Astrophysical Journal Letters; “Discovery of a Hypervelocity L Subdwarf at the Star/Brown Dwarf Mass Limit”; DOI: 10.3847/2041-8213/ad6607
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