Radiation from a dead star blasts away a small companion--a possible remnant of a planet--in this artist's concept. Astronomers have discovered that many of the dead stellar cores known as white dwarfs are ripping apart their planets and asteroids. Some have even digested some of the remains of their former planets, "polluting" their surfaces with heavy elements. This field of study is known as necroplanetology. [CfA/Mark A. Garlick]
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Necroplanetology
StarDate:
October 31, 2021A dead star in the constellation Virgo has taken its planetary system with it. It’s ripped apart the planets, leaving only rubble — chunks of rock and metal and clouds of dust. And even that won’t last long. The bigger pieces of rubble also are being pulled apart, with some of their remains falling onto the star.
The system is a target for the field of necroplanetology — studying dead or dying planets. The name was coined just last year, by astronomers who were studying the system in Virgo.
The star is a white dwarf — the small, hot, dead core of a star that was once much bigger, brighter, and more massive than the Sun. As astronomers studied the star, they found that its surface was “polluted” with iron and other heavy elements. The star’s gravity should pull such elements into its middle. The fact that they’re seen at the surface suggests they’re being added to the star.
Other observations showed that the star’s light dips every few hours — the result of chunks of debris passing in front of the star. The combination means that astronomers are watching as the star gobbles up its dead planets.
Necroplanetologists have discovered other white dwarfs that are pulverizing their planets. And they’ve seen similar behavior from stars that are in the prime of life. So stars aren’t always kind to their planets. They sometimes rip them apart and “eat” the remains — spooky behavior to think about on Halloween.
Script by Damond Benningfield
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