Remnants of Ancient Earth-Like World Seen Being Eaten by a Star


2022-11-15 15:12:37

Credit: University of Warwick-Dr Mark Garlick

Credit: University of Warwick-Dr Mark Garlick

The main sequence life of a star like the Sun may not end in a supernova like the most massive stars out there, but it will not be a quiet affair. As the star runs out of fuel and becomes unstable, it puffs up to an absolutely enormous size before blowing off its outer material while the core collapses into a small, ultradense white dwarf. For the Sun, that puffy red giant stage could extend as far as Mars, a process that could destabilize and destroy planets close enough.

We have seen white dwarf stars that have planets, suggesting that they can survive the process (or form after it). But, increasingly, scientists are finding that many exoplanets get eaten up by the white dwarf.

We can tell because of the 'pollution' by planetary elements in the atmospheres of white dwarf stars, the study of which is known as necroplanetology. And now, astronomers have discovered the oldest known example: An exoplanet devoured by a white dwarf that formed 10.2 billion years ago.

The white dwarf is around 90 light-years from Earth, incredibly small and dim, with an unusual hue redder than any other white dwarf star.

A second white dwarf star, unusually blue, formed 9 billion years ago. Both stars, the team found, are experiencing ongoing pollution by infalling planetary debris.