Astronomers using NASA‘s James Webb Space Telescope have just given a cosmic mystery a major plot twist.
The event in question – a sudden glow from a star about 12,000 light-years away – was initially explained by the fact that the star had swollen into a red giant and swallowed a neighboring planet, a typical story for some star systems.
But not this time. Webb’s penetrating infrared gaze, thanks to its MIRI and NIRSpec instruments, peered deep into the dusty aftermath with its mid-infrared (MIRI) and near-infrared (NIRSpec) spectrographs, and found the opposite. The star, ZTF SLRN-2020, was not inflating like a balloon – it looked calm. This means that the planet was not accidentally engulfed in explosive stellar behavior. Instead, the distant world was doomed to a slow orbital death spiral.
A new study published today in The Astrophysical Journal found that the unfortunate planet, roughly the size of Jupiter, orbited too close – closer to its star than Mercury is to our Sun. Over millions of years, this orbit decreased until the planet collided with the star’s atmosphere. According to study co-author Morgan McLeod, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics and the Massachusetts Institute of Technology, the planet’s material began to “smear around the star,” according to a Webb Space Telescope report. The planet’s history ended in a fiery collision with the star.
“Because this is such a new event, we didn’t quite know what to expect when we decided to point this telescope in its direction,” said Ryan Lau, lead author of the paper and an astronomer at the National Science Foundation’s NOIRLab, in the same release. “Thanks to its high resolution in the infrared, we are gaining valuable insights into the ultimate fate of planetary systems, including possibly our own.”
When the planet’s material hit the ZTF SLRN-2020, it likely caused a dramatic glow that caught the attention of astronomers. In fact, this is the first time a star has actively absorbed a planet, forcing astronomers to rethink their understanding of it.
This challenging observation was part of one of Webb’s Target of Opportunity programs, reserved for sudden cosmic oddities such as supernovae or, apparently, planetary death spirals. With the advent of next-generation telescopes such as the Vera Rubin Observatory and the Nancy Grace Space Telescope in Rome, we are likely to see many more of these grim stories of planetary end times.
