Oldest, coldest known white dwarf with many rings discovered by citizen scientist

The newfound star is challenging scientists' assumptions about how planetary systems evolve.


Whether scientists will find the elusive 'Planet Nine' remains a mystery, but on the road to finding an answer, they sure are chancing upon a number of undiscovered celestial bodies lurking in our vast solar system.

Melina Thévenot, a German Citizen scientist and member of the NASA-led Backyard Worlds: Planet 9 project, recently spotted something bizarre out there.

What she observed looked nothing like a planet or a 'brown dwarf' as per a EurekAlert report by Arizona State University. The report said that Thévenot originally thought 'J0207' may have been a brown dwarf that was too big to be a planet, but too small to be a star.

As it was later discovered that what Thévenot had found was a white dwarf — a star with a good amount of infrared brightness.

Oldest, coldest known white dwarf with many rings discovered by citizen scientist

The star, designated LSPM J0207+3331, is the oldest, coolest white dwarf known to be surrounded by a ring of dusty debris. Image: NASA Goddard Space Flight Center/Scott Wiessinger

"When Melina investigated further, she found that although the object had significant infrared brightness; it was not a nearby brown dwarf," Adam Schneider a research scientist at ASU said in a statement.

A white dwarf is also called a 'degenerate dwarf' that has a mass roughly equal to that of the Sun, but its volume roughly that of Earth's.

This white dwarf has been named LSPM J0207+3331 or J0207 for short, and is considered the oldest and coldest known white dwarf till date.

Also, this might even be the first one to have been found with multiple dust rings. The report said that the rings are speculated to be made up of warm dust and near continuous breakup of other "small rocky planetesimals" orbiting the dwarf.

Also as the white dwarf is extremely old and cold, the rings might remain a mystery.

"Curiously, the mid-infrared photometry of the disk cannot be fully explained by a geometrically thin, optically thick dust disk as seen for other dusty white dwarfs, but requires a second ring of dust near the white dwarf's Roche radius," the study's abstract reads.

John Debes, an astronomer at the Space Telescope Science Institute in Baltimore, said "This white dwarf is so old that whatever process is feeding material into its rings must operate on billion-year timescales," Debes said.

"Most of the models that scientists have created to explain rings around white dwarfs only work well up to around 100 million years, so this star is really challenging our assumptions of how planetary systems evolve."

The study was published in the Astrophysical Journal Letters.

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