Cosmic Space

Webb Telescope captures its first photo of alien planet

NASA has released the first direct image of an exoplanet taken by the James Webb Space Telescope — and although there’s no chance that this particular alien world could harbor life as we know it, the picture serves as an early demonstration of the observatory’s power.

“We’ve only just begun,” Aarynn Carter, a researcher at the University of California at Santa Cruz who led the analysis of the JWST image, said today in a NASA image advisory. “There are many more images of exoplanets to come that will shape our overall understanding of their physics, chemistry and formation.”

The planet in question, HIP 65426 b, is about 355 light-years away in the constellation Centaurus. Discovered five years ago, it’s a gas giant that’s roughly seven times as massive as Jupiter — and it’s about 100 times farther out from its parent star than Earth is from the sun.

That extreme distance from a dwarf star would make HIP 65426 b a prohibitively chilly ball of gas. But the distance also provides enough separation for JWST to distinguish the planet from the star.

“Obtaining this image felt like digging for space treasure,” Carter said. “At first, all I could see was light from the star, but with careful image processing I was able to remove that light and uncover the planet.”

This isn’t the first time an exoplanet has been directly imaged: Astronomers began capturing such images for nearly two decades. And it’s not the first time JWST has collected data about an exoplanet: The first batch of observations, released in July, included spectroscopic data about a “hot Jupiter” called WASP-96 b.

Although JWST is thought to be capable of capturing direct images of exoplanets that are smaller than HIP 65426 b — perhaps around the size of Uranus or Neptune — spectroscopic readings are expected to play a bigger part in the study of planetary habitability.

Just last week, JWST’s team reported detecting spectral signs of carbon dioxide in the atmosphere of WASP-39 b, a hot Jupiter that orbits a faraway sunlike star. It’s only a matter of time before the space telescope nails down similar data for more Earthlike planets as well.

The observations are reported in a pre-print paper that hasn’t yet been peer-reviewed, titled “The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems I: High Contrast Imaging of the Exoplanet HIP 65426 b From 2-16 μm.” The consortium behind the research was led by University of Exeter astrophysicist Sasha Hinkley, with Carter as the lead author.

By Alan Boyle

Mastermind of Cosmic Log, contributor to GeekWire and Universe Today, author of "The Case for Pluto: How a Little Planet Made a Big Difference," past president of the Council for the Advancement of Science Writing.

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