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The US space agency, NASA, has shared images of an “incredibly rare” brown dwarf that may be up to 13 billion years old.
A brown dwarf is a mysterious object located somewhere between a giant gas planet and a small star, but below the size that merges hydrogen like a star.
According to a study by astronomers at the California Institute of Technology in Pasadena, California, there may be more of these unusual “stars” in our galaxy than previously thought.
NASA researchers have said that the brown dwarf, officially named WISE 1534-1043, is 50 light years from Earth and does not resemble any of the 2,000 brown dwarfs found in our galaxy so far. According to Russia Today.
Weak in some wavelengths of light, bright in others, it travels around the Milky Way at half a million miles per hour, faster than any other local brown dwarf.
The unusual structure and speed of light helped the team determine the dwarf’s age between 10 and 13 billion years ago, twice the average age of other known brown dwarfs dating from a time when the Milky Way was very young and had a different chemical makeup.
This indicates that it has been present in the Milky Way since the early days, which means there could be more than initially thought, with as many as 100 billion brown dwarfs floating in interstellar space.
The brown dwarf was discovered by chance via the Wide Field Infrared Survey Explorer (NEOWISE) by citizen scientist Dan Caselden, who used an online program he had built to find these objects in the data collected by the telescope.
The “accidental” brown dwarf is between 13 and 80 times the size of Jupiter, but not enough to fuse elements like hydrogen into helium like a star does.
While brown dwarfs sometimes defy characterization, astronomers have a good understanding of their general properties, even of “crash”.
As brown dwarfs age, they cool down and their brightness changes with different wavelengths of light, in the same way that hot metals turn from white to red as they cool.
The “crash” confused scientists as it was weak at certain key wavelengths, indicating it was very cold, but bright in others, indicating high temperature.
“This object has defied all of our expectations,” said Davey Kirkpatrick, astrophysicist at the Caltech Infrared Processing and Analysis Center (IPAC).
He noted that the 10 to 13 billion year old “crash” means it could have formed when our galaxy was much younger and had a different chemical makeup.
“If so, it’s likely that there are other older brown dwarfs lurking near the galaxy,” the researcher explained.
To find out why it has contrasting properties, with some suggesting it’s cold and others hotter, astronomers turned to the Keck Observatory in Hawaii.
They used the telescope to observe the object in a wider range of wavelengths of light, especially infrared, but it was too faint to be detected at all.
This suggestion confirmed that it was very cold, which means that it is also likely to be outdated.
They then set out to determine whether the power outage was due to the crash being further from the ground than expected. But it wasn’t, according to precise distance measurements by NASA’s Hubble and Spitzer space telescopes.
After determining the object’s distance, about 50 light years from Earth, the team realized that it was moving rapidly, at about half a million miles per hour. It’s much faster than any other brown dwarf known to exist this distance from Earth, meaning they may have circled the galaxy for a long time, encountering massive objects accelerating their gravity.
“It’s not surprising to find a brown dwarf this age, but it’s surprising to find a dwarf in our backyard,” said Federico Marocco, astrophysicist at Caltech’s Center for Infrared Processing and Analysis (IPAC). who conducted the new observations using the Keck and Hubble telescopes.
“We expected brown dwarfs to exist at this age, but we also expected them to be incredibly rare. The luck of finding one so close to the solar system could be a lucky coincidence, or tell us that it’s more common than we thought. “
“This finding tells us that there is more diversity in brown dwarf formations than we have seen so far,” says Kirkpatrick. “There are probably more exotic things, and we need to think about how to find them.”
The results were published in full in Astrophysical Journal Letters.
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