Webb Telescope captures image of ‘super-Jupiter’ exoplanet

(CN) — Images taken with the James Webb Space Telescope have shed new light on a large gaseous planet that previous data had indicated was much smaller.

Published in Nature on Wednesday, the new research from scientists with the Max Planck Institute for Astronomy has upended what was previously known about the gas giant exoplanet known as Eps Ind Ab.

“We were excited when we realized we had imaged this new planet,” said Elisabeth Matthews, who is the main author of the article. “To our surprise, the bright spot that appeared in our MIRI images did not match the position we were expecting for the planet.”

Matthews and her team used the Mid-Infrared Instrument, or MIRI, equipped on the James Webb Space Telescope to capture the image of the planet.

The MIRI is extremely useful to researchers because it has both a camera and spectrograph that can see light in the mid-infrared, which is not detectable by human eyes.

In the context of the research, an image refers to a bright dot that appears visible, which gives scientists direct evidence of the exoplanet.

In particular, cold planets like the exoplanet are difficult to detect using other methods because their orbits tend to be far away from their host star and are harder to monitor. When scientists can only study a small section of a planet’s orbit, it makes it more challenging to glean information.

The MIRI does not have this issue because it can detect wavelengths within the electromagnetic spectrum where cold objects appear bright.

“Previous studies had correctly identified a planet in this system but underestimated this super-Jupiter gas giant’s mass and orbital separation,” Matthews said.

Giant gas exoplanets, like Eps Ind Ab, are called super-Jupiters when they are more massive than the Jupiter in our solar system. Eps Ind Ab, which has a mass six times than that of Jupiter, is also the oldest and coldest exoplanet ever imaged.

Despite being previously detected, the researchers call Eps Ind Ab a “new planet,” because their estimates of its size and orbit around its host star differed greatly from previous studies.

The point of light detected by the researchers was also not where previous data had led them to expect. 

“We discovered a signal in our data that did not match the expected exoplanet,” Matthews said. “But the planet still appeared to be a giant planet.”

The researchers used imaging data from 2019 to rule out that the light was coming from an unexpected or unknown source. 

“It is always hard to be certain, but from the data, it seemed quite unlikely the signal was coming from an extragalactic background source,” said Leindert Boogaard, a MPIA scientist and co-author of the article.

Using new and previously gathered data, the scientists attempted to study the planet’s atmosphere, which given its colors could indicate substantial amounts of heavy elements like carbon.

Carbon builds molecules such as methane, carbon dioxide and carbon monoxide which are commonly found on gas-giant planets like Eps Ind Ab. However, more research will be needed to make a proper conclusion.

“Our next goal is to obtain spectra which provide us a detailed fingerprint of the planet’s climatology and chemical composition,” said Thomas Henning, Emeritus Director at MPIA and co-author of the article.

Matthews hopes that the research can help further a better understanding of gas planets like Eps Ind Ab.

“In the long run, we hope to also observe other nearby planetary systems to hunt for cold gas giants that may have escaped detection,” Matthews said. “Such a survey would serve as the basis for a better understanding of how gas planets form and evolve.”