Space & Astronomy
Mystery object is hurtling through the galaxy
By T.K. Randall
September 3, 2021 · 10 comments
'The Accident' is one unusual (and very old) brown dwarf. Image Credit: NASA / JPL-Caltech
Astronomers have obtained their first detailed look at a peculiar Milky Way object known as 'The Accident'.
Originally detected using NASA's Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) telescope, this object is not quite a star, yet not quite a planet either.
It fits into a class of objects known as brown dwarfs (or failed stars) - a type of star that can be up to 80 times the diameter of Jupiter, yet with a mass significantly lower than that of the Sun.
Brown dwarfs are thought to start off their life as a regular star but their mass prevents them from being able to sustain nuclear fusion, causing them to dim and fade away over billions of years.
This particular example, however, is quite unusual even for a brown dwarf.
Known as 'The Accident' because it was discovered 'photo-bombing' a group of other candidates, the object appears to possess characteristics consistent with both young and old brown dwarf stars.
"This object defied all our expectations," said lead study author Davy Kirkpatrick.
A further study of the object revealed that it is moving much faster than the typical brown dwarf - suggesting that it may have been flung around the galaxy for billions of years.
Its atmosphere is also strangely devoid of methane - indicating that it could be twice as old as the other brown dwarf stars that astronomers have studied.
"It's not a surprise to find a brown dwarf this old, but it is a surprise to find one in our backyard," said study co-author Federico Marocco.
"We expected that brown dwarfs this old exist, but we also expected them to be incredibly rare."
"The chance of finding one so close to the solar system could be a lucky coincidence, or it tells us that they're more common than we thought."
Source: Live Science
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Milky Way, Galaxy
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