A surprisingly low supply of methane may explain how a planet around a nearby star became strangely inflated, according to new observations. The James Webb Space Telescope (JWST(. The finding shows that planetary atmospheres can swell to remarkable amounts without using esoteric theories about planet formation), astronomers say.
“The Webb data tell us that planets like WASP-107 b didn’t have to form in some special way with a super-small core and a huge gas envelope.” Michael Lineextrasolar planetologist from Arizona State University, said va declaration. “We can take something similar instead Neptunewith a lot of rocks and not so much gas, just turn up the heat and turn it up to make it look the way it does.”
Discovered in 2017 by the Wide Angle Search for Planets (WASP) consortium, WASP-107 b, located about 200 light years of Earth in Virgo constellation, is among the lightest of the more than 5,000 exoplanets found so far. Although it is almost as big as JupiterWASP-107 b weighs only 12% by mass gas giantmass, equivalent to only 30 Earths. For context, one mass of Jupiter equals approx 318 mass of Earth. This planet is so bloated, the team says, that its density can be compared to a microwave oven.
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From previous observations of the size, mass and age of WASP-107 b, astronomers suspected that the planet has a small rocky core surrounded by a rich reservoir of hydrogen and helium gases. However, such a scenario could not fully explain the remarkably inflated sphere, which despite orbiting its star at a distance of seven minutes between Quicksilver and our sun, does not receive enough energy from its star to match its cotton-like density. Alternatively, if the planet’s core actually contained more mass than expected, the researchers say the atmosphere would shrink as the planet cooled. timemeaning it would turn out to be smaller than observed.
Now using JWST data – combined with previous observations from Hubble Space Telescope — Two independent teams of astronomers may have solved the puzzle. In short, they found that the methane in the planet’s atmosphere is one-thousandth of what would be expected for this world. Because methane is unstable at high temperatures, astronomers say the surprisingly low amount is evidence that the gas from deep within the planet is “vigorously mixing with cooler layers above.” David Sing Johns Hopkins University (JHU) in Maryland, which led one of the two new studies, said in a statement. “The fact that we detected so few, even though we detected other carbon-containing molecules, tells us that the interior of the planet must be significantly hotter than we thought.”
The additional heat likely comes from the fact that WASP-107 b circles its star every 5.7 days in an orbit that isn’t a perfect circle, the researchers say. The constant gravitational pull of the star on WASP-107 b, whose distance from its star is constantly changing, stretches and contracts the profile of the planet, heating it up. A similar force on Earth Moon causes ebb and flow.
The planet’s hot core, combined with tidal heating from its star, also changes the chemistry of the gases deep inside the planet, Zafar Rustamkulovwho is a postgraduate student at JHU and a co-author of one of the two new studies, said va declaration from the university. “We think that this heat causes the chemistry of the gases to change, specifically destroying methane and creating increased amounts of carbon dioxide and carbon monoxide.”
In 2020, a team of astronomers, including Sing, detected helium in the atmosphere of WASP-107 b, marking the first time this discovery has been seen on an exoplanet. The element, which was tentatively spotted on Earth in 2018 before its existence there was confirmed two years later, was seen stretching far into space as a faint cloud. As the planet’s atmosphere has so far shed, astronomers say ultraviolet radiation from the star WASP-107 b is slowly stripping the world of air — about 0.1% to 4% of its atmospheric mass every billion years, to be exact, leading to the formation of the comet . -like a tail trailing behind a ball.
Thanks to the planet’s extremely puffy nature, astronomers can peer about 50 times deeper into its atmosphere than a world like Jupiter. Last year, for example, observations of the atmosphere of WASP-107 b on JWST showed this it rains sand on the planet.
This research is described in two studies published Monday (May 20) in the journal Nature.