Published 08:02 IST, September 17th 2020
NASA spots first ever 'survivor’ planet orbiting close to star's corpse
NASA on Wednesday has found the first-ever planet to be closely orbiting around a white dwarf star, which is the dense leftover of its Sun-like star.
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National Aeronautics and Space Administration (NASA) on Wednesday has found the first-ever planet to be closely orbiting around a white dwarf star, which is the dense leftover of its Sun-like star that is only 40 percent larger than Earth. The new data from NASA’s Transiting Exoplanet Survey Satellite (TESS) and its retired Spitzer Space Telescope appear to indicate that the planet known as 'WD 1856 b' is intact and in close orbit around its star. Previously scientists believed that such a search would be futile as the creation of the white dwarf was expected to destroy any planets that came too close.
'The Jupiter-size object, called WD 1856 b'
"The Jupiter-size object, called WD 1856 b, is about seven times larger than the white dwarf, named WD 1856+534. It circles this stellar cinder every 34 hours, more than 60 times faster than Mercury orbits our Sun", NASA said in its official statement.
“WD 1856 b somehow got very close to its white dwarf and managed to stay in one piece,” said Andrew Vanderburg, an assistant professor of astronomy at the University of Wisconsin-Madison. “The white dwarf creation process destroys nearby planets, and anything that later gets too close is usually torn apart by the star’s immense gravity. We still have many questions about how WD 1856 b arrived at its current location without meeting one of those fates", he added.
According to NASA, when a star like the Sun runs out of fuel, it starts to swell up, going to hundreds of thousands of times its previous size, and turns into a cooler red giant. The gas is then thrown out into space, which causes it to shrink down again, casting out 80 percent of its mass and leaving the remnants behind in the form of a white dwarf, NASA said.
When this occurs, anything that is closer or nearby usually is engulfed and burned away. If WD 1856 b was as close to the star as it is today, it would have suffered the same fate however researchers hypothesize that it actually began about 50 times further away, and was pulled in.
"We've known for a long time that after white dwarfs are born, distant small objects such as asteroids and comets can scatter inward towards these stars. They're usually pulled apart by a white dwarf's strong gravity and turn into a debris disk," said co-author Siyi Xu, an assistant astronomer at the international Gemini Observatory in Hilo, Hawaii, which is a program of the National Science Foundation's NOIRLab.
Furthermore, WD 1856 b is thought to be no more than 14 times the size of Jupiter. Based on the information the scientists were able to gather as it passed in front of the star, as well as the age of the white dwarf itself. Further research is required to confirm that conclusion and allow scientists to decisively know that they have spotted the first such example of a planet in close orbit around a white dwarf.
"There is currently no evidence suggesting there are other worlds in the system, but it’s possible additional planets exist and haven’t been detected yet", NASA said. Adding further it said they could have orbits that exceed the time TESS observes a sector or are tipped in a way such that transits don’t occur. The white dwarf is also so small that the possibility of catching transits from planets farther out in the system is very low, it said.
08:02 IST, September 17th 2020