Astronomers Were Looking for a Planet, but They Didn't Expect This One

The Epsilon Indi star system is already pretty weird, but this surprising new planet just made it even weirder.

BY KIONA SMITH
JULY 24, 2024



Episolon Indi is a trio of stars, which is a complicated situation already — but two of them aren’t even real stars; they’re brown dwarfs, objects just a smidgeon too small to be stars, but several smidgeons too big to be planets. And now the system boasts an enormous gas giant in its outskirts, where astronomers didn’t expect it to be.

A team of astronomers recently used the James Webb Space Telescope (JWST)’s MIRI instrument to capture images of a gas giant orbiting a nearby star. Earlier studies had predicted that the star should have a giant planet, but no one expected the planet astronomer Elisabeth Matthews and her colleagues actually found in JWST’s data: a gargantuan beast of a world, six times the mass of Jupiter and orbiting three times farther from its star than Jupiter does from the Sun.

Matthews (of the Max Planck Institute for Astronomy) and her colleagues published their findings in the journal Nature.

A GIANT SURPRISE

Matthews and her colleagues pointed JWST’s Mid-Infrared Instrument, or MIRI, at the nearby star system Epsilon Indi, which is home to one small orange star, just a little smaller and cooler than our Sun, and a pair of brown dwarfs (objects much too large to be planets, but not quite massive enough to be stars). Other astronomers had previously noticed that Epsilon Indi A, the orange star, had a slight wobble, as if it were being pushed and pulled by the gravity of a giant gas planet in its orbit. But no one had ever actually seen that planet, and the researchers thought JWST would be up to the challenge.

More:
https://www.inverse.com/science/astronomers-discover-epsilon-indi-ab-planet-jwst