Astronomers have mined data from the Kepler Space Telescope, NASA’s planet-hunter, to discover a miniature planet in the act of being shredded by its star. The discovery was made as part of the K2 mission, Kepler’s post-main phase repurposing.
What they found was a curious transiting signal of an object that seemed to exhibit a “cometary” signature—an indication of something being vaporized. The object is about the size of a large asteroid, something like Ceres in our own Solar System, in a close, 4.5-hour orbit about the white dwarf WD 1145+017.
The discovery is more than coldly academic—it may be a vision of our own Solar System’s distant future. White dwarfs are the cinders of dead stars, packing something like half the Sun’s mass in a volume scarcely larger than the Earth’s; our own life-giving Sun is expected to become one in eight billion years or so.
With current technology, it is, of course, impossible to say whether the tortured planetesimal is the ancient remnant of some once life-bearing planet, like the Earth, or whether it’s something that formed more recently, from the cast-off material of its dying star.
In any case, it seems to answer the question of why certain white dwarfs possess heavier elements than the standard hydrogen/helium in their atmospheres—they consume their own retinue of worlds, polluting their pure gaseous envelopes with the crumbs of their cannibalistic repasts.