Astronomers have found dead stars smeared with the remains of shredded exoplanets.
An exoplanet and a debris disk surrounding a polluted white dwarf star. (Image Credit: NASA/JPL-Caltech).
New Delhi: White Dwarf are the final stages of stellar evolution, and are the exploded cores of dead stars that continue to burn. Astronomers have identified hundreds of polluted white dwarf stars in the Milky Way, which are elusive stars that are actively consuming planets in their orbit. The identification of these stars is a valuable resource for studying the remote interiors of remote, demolished exoplanets.
A destroyed planet in orbit around a White Dwarf star. (Image Credit: NASA, ESSA, Joseph Olmsted, STScI).
In another six billion years, the Sun is expected to balloon up into a red giant, use up all its fuel, violently dump the outer layers in a supernova explosion, and then cool off as a white dwarf star. The planets orbiting white dwarf stars can on occasion be drawn in by the gravity of the star, then shredded into a debris disk surrounding the star and consumed. White Dwarf stars are made up of mostly hydrogen and helium, and the presence of any other elements can be attributed to external sources, or consumed planets.
How to spot a polluted white dwarf
So far, astronomers had to manually review mountains of survey data to identify signs of these elusive stars, which made them challenging to identify. Follow-up observations were often necessary to confirm any flagged white dwarf stars. For the new study, the researchers used a novel form of artificial intelligence called manifold learning, that accelerated the process of identifying such polluted white dwarfs.
A paper describing the findings has been published in the Astrophysical Journal. One of the study authors, Malia Kao says, “For polluted white dwarfs, the inside of the planet is literally being seared onto the surface of the star for us to look at. Polluted white dwarfs right now are the best way we can characterize planetary interiors.” The method has increased the number of known polluted white dwarf stars by a factor of ten.
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Shambhu Kumar is a science communicator, making complex scientific topics accessible to all. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
