Melina Thevenot, a volunteer scientist working with NASA's Backyard Worlds: Planet 9 project, has found the oldest and coldest known white dwarf star, the US space administration has announced.

The star, named J0207, is an Earth-sized remnant of a sun-like star located 145 light years away in the Capricornus constellation. Due to its temperature of 5,800 degrees Celsius (10,500 Fahrenheit), NASA believes the star is about 3 billion years old.

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NASA said in a statement on Tuesday that Thevenot's discovery "is forcing researchers to reconsider models of planetary systems and could help us learn about the distant future of our solar system."

Thevenot, a citizen scientist from Germany, had been searching for brown dwarfs, which are larger than planets but smaller than stars, while working in the European Space Agency's archives when she found something much brighter and much further away.

She initially thought it was bad data, according to NASA, but passed her findings to astronomer John Debes and astrophysicist Marc Kuchner, both of whom are based in Maryland. They then contacted Adam Burgasser, a collaborator with the University of California, San Diego, to use the Keck II telescope in Hawaii to study the white dwarf.

"That is a really motivating aspect of the search," said Thevenot as part of NASA's statement. "The researchers will move their telescopes to look at worlds you have discovered. What I especially enjoy, though, is the interaction with the awesome research team. Everyone is very kind, and they are always trying to make the best out of our discoveries."

Kuchner, the leader of the Backyard Worlds project, said working with citizen scientists "always leads to surprises."

dv/cmk (dpa, NASA)

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