James Webb Space Telescope reveals mysterious planet glowing eerily

This artist’s impression shows the nebulous-Neptune-sized planet recently observed with the James Webb Space Telescope.

NASA/JPL-Caltech/R. Hurt (IPAC)

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NASA/JPL-Caltech/R. Hurt (IPAC)

This artist’s impression shows the nebulous-Neptune-sized planet recently observed with the James Webb Space Telescope.

NASA/JPL-Caltech/R. Hurt (IPAC)

A mysterious, cloud-shrouded planet that has puzzled astronomers for years is less hot than expected — and surprisingly bright.

According to a new report published in the journal, the James Webb Space Telescope has uncovered what astronomers have been trying to understand since it was first discovered a decade ago around another star known as mini-Neptune. the nature.

Our own solar system does not have this planet, known as GJ 1214b. It is larger than the rocky planets like Earth, but still smaller than any of the ice or gas giants of our system.

And yet studies show that such planets — often called super-Earths or mini-Neptunes — are incredibly common in our galaxy.

“Is it like a big, scaled-down Earth? Is it a small, scaled-down Neptune? Is it something completely different that we’ve never seen before, maybe called a water world, where the atmosphere is vapor?” Eliza Kempton, an astronomer at the University of Maryland in College Park, wonders.

Astronomers zero in on GJ 1214b in particular because they say it’s the most accessible planet of its kind to observe. It orbits a relatively nearby smaller but brighter star, only 48 light-years away.

Trouble is, the planet has proven remarkably resistant to giving up its secrets.

“This planet is a challenge. We’ve been trying to understand its atmosphere for a long time,” says Kempton.

He explains that sometimes astronomers can learn about a planet by watching it pass in front of its star and analyzing the starlight that filters through its atmosphere. But that strategy didn’t work for this one, because the planet was completely covered by a thick blanket of clouds or haze.

The recently launched James Webb Space Telescope, however, will let astronomers see the planet in a new way. This telescope detects infrared light, which can essentially be thought of as heat.

“What we tried to do was observe the heat coming from the planet, and we succeeded in doing that,” says Kempton.

The telescope watched the planet orbit its star, which happens every 38 hours. “We were able to effectively map the temperature of the planet at all its different stages,” says Kempton.

The planet’s daytime temperature is about 530 degrees Fahrenheit — too hot for any known life, but still much cooler than researchers expected.

That means instead of absorbing all the energy coming from its star, the planet must be more reflective and able to scatter half of the incoming energy back.

“We didn’t expect the planet to be so reflective, and we actually expected the opposite,” says Kempton.

Scientists previously thought the clouds might be made up of some kind of dark, sooty haze, but they say that’s not consistent with reflecting all the light.

“That tells us something about what these clouds or hazes in the atmosphere are made of, and that’s a really new big question,” he says, adding that scientists are beginning to try to create chemical hazes in the lab with similar properties. To see what would happen.

The telescope also saw signs that the planet’s atmosphere was not hydrogen-rich, indicating that Neptune was not simply scaled-down, and there was evidence of water vapor and methane.

“We’re pretty confident that there’s water there,” Kempton says, adding that the planet is too hot for water to exist as a liquid.

The James Webb Space Telescope should be seeing more planets in this size range, he says, revealing whether it’s a freak or a true representative of this class of planets.

The new findings attracted planet researcher Laura Kreidberg with Germany’s Max Planck Institute for Astronomy, who was not part of the research team but has previously used the Hubble Space Telescope to peer at GJ 1214b.

They called this planet a “white whale” for scientists who study planets outside our solar system, because it is so difficult to characterize.

“It’s great to finally see some of the secrets being revealed,” Kredberg says. “I certainly didn’t expect the atmosphere to be so flashy. It wasn’t even on my radar.”

“We need to go back to the drawing board,” he adds, “to understand why the planet is shining.”

It looks like an entirely new kind of planet, he says.

“Based on what we’re seeing, it’s more like Neptune than Earth, but it’s really its own thing,” he says. “Neptune has an atmosphere made mostly of hydrogen. GJ 1214b appears to have an atmosphere made mostly of water.”

That puts the planet “into a category of its own in a way that’s never been decided before,” says Kreidberg. “So it’s really in between, a new class of planet that we’re looking at.”

He thinks they’re so common everywhere in the galaxy, “It’s really strange that the solar system doesn’t have one.”

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