A volunteer citizen scientist working with Backyard Worlds: Planet 9, a NASA-funded project that aims to find new Brown Dwarfs and the elusive Planet Nine, has made a remarkable discovery.
Coldest And Oldest Known White Dwarf
Melina Thévenot initially thought that the object was a cold brown dwarf. Brown dwarfs are low-temperature objects that are too large to be planets, but too small to be stars.
It turns out, however, the celestial object is a white dwarf, the remnant left after a sun-like star dies. The object, known as LSPM J0207+3331 or J0207, lies 145 light-years away in the Capricornus constellation.
"This object was found by Melina Thévenot of Germany using the Backyard Worlds project. She originally thought it might be a cold brown dwarf," said Adam Schneider, from the School of Earth and Space Exploration at Arizona State University, who was part of the team that reported the discovery.
"When Melina investigated further, she found that although the object had significant infrared brightness; it was not a nearby brown dwarf,"
Further investigations revealed that the object is also the coldest and oldest white dwarf ever detected. Astronomers estimate is about 3 billion years old.
J0207 is also surrounded by rings of dust and debris. The object has infrared excess believed to be radiating from a warm and dusty circumstellar disk. These disks are likely the result of the continual breakup of small rocky planetesimals orbiting the white dwarf.
Researchers think it could be the first known white dwarf with multiple rings.
"We report the discovery that the candidate white dwarf LSPM J0207+3331, via the Backyard Worlds: Planet 9 citizen science project and Keck Observatory follow-up spectroscopy, is hydrogen dominated with a luminous compact disk (L IR/L sstarf = 14%) and an effective temperature nearly 1000 K cooler than any known white dwarf with an infrared excess," Schneider and colleagues wrote in their study.
The findings were published in the in The Astrophysical Journal Letters on Tuesday, Feb. 19.