NASA's Image Of An Alien Planet 12 Light Years Away Gives Astronomers Chills

An international team of astronomers employing NASA’s Webb Space Telescope captured an exoplanet 12 light years away, and in a location that may be familiar to fans of science fiction. The alien planet orbits the K-type star Epsilon Indi A, which is around the same age as Earth’s Sun, but is slightly cooler.

The exoplanet, Epsilon Indi Ab, was observed using the coronagraph on Webb’s MIRI (Mid-Infrared Instrument). The exoplanet, which is several times the mass of Jupiter, is also one of the coldest exoplanets imaged to date. Exoplanets that were previously imaged tended to be the youngest and hottest, as they were still radiating most of the energy from when they first formed. So, being able to capture an image of a much cooler exoplanet such as Epsilon Indi Ab was exciting for the team.

“Our prior observations of this system have been more indirect measurements of the star, which actually allowed us to see ahead of time that there was likely a giant planet in this system tugging on the star,” said team member Caroline Morley of the University of Texas at Austin. “That’s why our team chose this system to observe first with Webb.”


Elisabeth Matthews of the Max Planck Institute for Astronomy in Germany explained cold planets, like Epsilon Indi Ab, are very faint, and most of their emission is in the mid-infrared spectrum. She added that this makes Webb an ideal candidate for conducting observations, because this type of observation required “good spatial resolution to separate the planet and the star” in the images, and Webb’s mirror was “extremely helpful in this aspect.”

If Epsilon Indi sounds familiar to fans of Star Trek, it’s because it was an actual system used by the sci-fi series in its storytelling. The system also made its way into Halo lore, designated UC.901.9081 by the Forerunners.

“Astronomers have been imagining planets in this system for decades; fictional planets orbiting Epsilon Indi have been the sites of ‘Star Trek’ episodes, novels, and video games like Halo,” added Morley. “It’s exciting to actually see a planet there ourselves, and begin to measure its properties.”

Matthews also noted that the observation was not what the team expected. The team had thought Epsilon Indi Ab would be smaller, due to the radial velocity indications of its presence. However, it turned out to be twice as massive, and a little farther away from its star with a different orbital path as they expected.

The atmosphere also ended up being a surprise, as it differed from prior model predictions, as the planet is fainter than expected in shorter wavelengths. This leads the team to believe this may mean there is a significant methane, carbon monoxide, and carbon dioxide in the planet’s atmosphere that are absorbing the shorter wavelengths.

Observations like that of Epsilon Indi Ab, and future observations by both Webb and NASA’s upcoming Nancy Grace Roman Space Telescope, are providing critical information that will help astronomers detect other similar planets. NASA remarked, “These results will pave the way for future missions to study worlds that are even more Earth-like.”