“Accident”, the mysterious object in the Milky Way that interests astronomers
3 min read
They’re not exactly stars or planets, but they are something in between. This is the definition of an alien space object known to astronomers as a brown dwarf.
Now scientists at the California Institute of Technology (Caltech) have accidentally discovered a space object similar to a brown dwarf, but with some special properties. The mysterious object was called “The Accident”. The discovery was published in the scientific journal Astrophysical Journal.
“This object defies all our expectations,” said Davey Kirkpatrick, a study co-author and an astrophysicist at the California Institute of Technology (Caltech).
The study suggests that the “accident” may be between 10 billion and 13 billion years old, making it at least twice the age of other brown dwarfs previously discovered.
This indicates that they formed when our galaxy was very young and had a different chemical composition.
“If that’s the case, it’s likely that there are a lot of these ancient brown dwarfs lurking in our galactic region,” Kirkpatrick adds.
different brown dwarf
Scientist Dan Casselden discovered the “accident,” officially known as WISEA J153429.75-104303.3, by sheer luck, as it bears little resemblance to any other brown dwarf found in the galaxy to date, according to a statement from the space agency.
As brown dwarfs age, they cool and change their luminosity at different wavelengths, just as hot metals change color when they cool.
This illustration shows a cool dark brown dwarf in space.
Photo: IPAC/CALTECH
This object piqued the interest of scientists because its glow is not typical of those seen in other aging brown dwarfs.
It emits faint light at some wavelengths, indicating that such objects are very cold, but at the same time appear more bright elsewhere, indicating that they also have warmer regions.
“It’s no surprise to find such an old brown dwarf, but it’s surprising to find one in our backyard,” said Federico Marocco, Davy Kirkpatrick Fellow at Caltech and one of the study’s authors.
“We expected brown dwarfs to exist at this age and we also expected them to be incredibly rare,” says the astrophysicist, who is responsible for directing observations with the Keck and Hubble telescopes.
800,000 km/h faster
Using ground-based telescopes at the WM Keck Observatory in Hawaii, the researchers attempted to observe the accident with additional infrared radiation.
But it looked so weak that it could not be detected, which confirms that it is very cold and therefore very old.
The researchers estimate that the speed with which it is spinning is further evidence that it has been in the galaxy for a long time, because it pulls on massive objects that cause them to accelerate with gravity.
The accident is located about 50 light-years from Earth and orbits about 800,000 km / h faster than all other brown dwarfs detected at a similar distance from our planet, according to the study.
The study highlighted that another characteristic of the accident was that it contained low levels of methane, compared to most other brown dwarfs found, strengthening the argument that it formed more than 10 billion years ago. At that time, the galaxy was made almost entirely of hydrogen and helium, and carbon was not needed to form methane.
“The possibility of finding something this close to the solar system may be a happy coincidence or mean that it is more common than we think,” Marocco concludes.
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