May 4, 2023 - Science

Distant star caught swallowing its own planet

Artist's illustration of a planet being absorbed by its star. Image: K. Miller/R. Hurt (Caltech/IPAC)

A Sun-like star 12,000 light-years from Earth has been spotted eating one of its planets.

Why it matters: The first-of-its-kind discovery is a glimpse into the future of our solar system. In about 5 billion years, our Sun will expand, consuming Mercury, Venus and even Earth.

  • "The confirmation that Sun-like stars engulf inner planets provides us with a missing link in our understanding of the fates of solar systems, including our own," Kishalay De, a researcher at MIT and lead author of a new study in Nature detailing the discovery, said in a statement.

What they found: When the team of scientists started observing the star with the Zwicky Transient Facility, they saw it brighten in optical light — the spectrum of light the human eye can see.

  • But followup observations with other instruments showed the star was also brightening in infrared light, which could point to the creation of dust in the system.
  • The team of scientists then figured out the dust was being created as a planet fell into its star's expanding atmosphere, displacing hot gas from the star that then cooled and created dust. Fragments of the planet also blew outward from the star, producing more dust.
  • "The planet plunged into the core of the star and got swallowed whole. As it was doing this, energy was transferred to the star," De added. "The star blew off its outer layers to get rid of the energy. It expanded and brightened."

The bottom line: Learning more about these distant star systems is bringing us closer to truly understanding the eventual fate of the Earth and our Sun.

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