Somewhere in Virgo, a planet is dying.
That's what astronomers from the Harvard-Smithsonian Center for Astrophysics revealed today. They have spotted a rocky object wobbling around a white dwarf—the half-corpse of a star that has burst out of its outer layers, leaving only an incredibly dense core. Some call them "death stars."
The astronomers noticed something was up while monitoring NASA's Kepler 2 data. Kepler 2 watches what is happening in solar systems outside our own. The astronomers found that this star was blinking about every 4.5 hours, evidence that something was orbiting it and crossing our field of vision regularly. The white dwarf, which we'll call Carl, is about 520,000 miles from its orbiting planet, and both are in the constellation Virgo. It makes sense that Carl would be tearing apart his neighbors in Virgo, because Virgos are, as anyone knows, very meddling. (Just kidding; astrology is pseudoscience. Sorry.)
The planet orbiting Carl is actually the first planetary object to be spotted circling a white dwarf, and it confirms a previous scientific hypothesis. Astronomers have been aware for some time that white dwarfs occasionally show signs of metals like silicon and iron in their light spectrums. That doesn't totally make sense, because the dwarves themselves are composed mainly of carbon, oxygen, and a little hydrogen or helium. Any metals would be too heavy, and would sink to the center of the white dwarf, where we can't detect them. So that meant the metal had to be coming from somewhere else. And scientists theorized that maybe it was an orbiting object. Now they know they were right.
"We now have a 'smoking gun' linking white dwarf pollution to the destruction of rocky planets," says Andrew Vanderburg, the lead author of the paper announcing the finding, in a press release.
There also appear to be other materials orbiting Carl, and what Harvard calls "an extended cloud of dust" around the dying star. But the planet at the center of the discovery is particularly prominent, since it dims Carl's lights by almost half—that's quite a flicker.
The planet won't last for long. Because it is close to the intensely hot white dwarf, it will eventually be ripped apart and scattered into thin metal dust, just like other objects that crossed Carl's path.
"This is something no human has seen before," said Vanderburg. "We're watching a solar system get destroyed."
The findings will be published this week, in the journal Nature.
