One very peculiar brown dwarf is unlike anything astronomers have ever seen. In fact, it was discovered completely by chance and that’s why it has been nicknamed “The Accident” (its official name is WISEA J153429.75-104303.3). Brown dwarfs are too large to be a planet but too small to be a star – basically, they have a mass that’s in between giant planets (like Jupiter and Saturn) and stars.
The brown dwarf was found by Dan Caselden – a citizen scientist who was looking through data collected by NASA’s Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE). In his own program that he created, Caselden eliminated all stationary objects that sent off infrared light such as stars. He then focused on moving objects that could possibly be brown dwarfs. While focusing on one object in particular, he realized that it was in fact a brown dwarf but what he found was much more incredible as it was completely unique from other brown dwarfs which was why the program didn’t initially find it.
“The Accident” is incredibly odd as it appeared faint in some wavelengths (meaning that it was extremely cold and old), but showed up bright in other wavelengths (suggesting it was much hotter). According to the paper, the researchers believe that the reason why it appeared faint in some wavelengths and brighter in others is because it has barely any methane which indicates that it was created when our Milky Way Galaxy was in its very young stages and had very little carbon (methane consists of hydrogen and carbon).
That is why experts believe that “The Accident” is between 10 and 13 billion years old. For comparison, other brown dwarfs that have been discovered are about half that age. Furthermore, our galaxy is approximately 13.6 billion years old with our Solar System being about 4.5 billion years in age.
With help from NASA’s Hubble and Spitzer Space Telescopes, experts were able to determine that the brown dwarf is located about 50 light-years away from our planet and moving extremely fast at nearly 500,000 miles per hour (800,000 kilometers per hour). This is much faster than other brown dwarfs located about the same distance away from us. “This object defied all our expectations,” stated Davy Kirkpatrick who is an astrophysicist at IPAC at Caltech in Pasadena, California. (A video showing “The Accident” moving through space can be viewed here.)
The study was published in the Astrophysical Journal Letters where it can be read in full.