A surprisingly low supply of methane may explain how a planet surrounding a nearby star became strangely bloated, according to new observations from the European Space Agency. James Webb Space Telescope (JWST). Astronomers say the results show that planetary atmospheres can swell to noticeable amounts without using esoteric theories about planetary formation.
“Webb’s data tell us that planets like WASP-107 b didn’t have to form in a strange way with a very small core and a massive gaseous atmosphere.” Michael LaneAn exoplanet scientist at Arizona State University said in A statement. “Instead, we could take something more like Neptune“With a lot of rock and not a lot of gas, you just increase the temperature, and then turn it up and it looks the same.”
Discovered in 2017 by the Wide-Angle Planetary Search (WASP) consortium, WASP-107 b is located approximately 200 kilometers away. Light year from Land In the Virgo constellationIt is among the lightest exoplanets discovered so far, of which there are more than 5,000 planets. Although it is almost as large JupiterWASP-107 b weighs only 12% of its own weight Gas giantIts mass is equivalent to only 30 ground balls. For context, one Jupiter mass is about 318 Earth mass. The team says the planet is so bloated that its density can be likened to a microwaved marshmallow.
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From previous observations of WASP-107 b’s size, mass, and age, astronomers suspected that the planet had a small rocky core surrounded by a rich reservoir of hydrogen and helium gases. However, such a scenario fails to fully explain the inflated orb, which, despite the fact that it orbits its star at a distance of one-seventh the distance from its own star. Mercury Our sun does not receive enough energy from its star to account for its cotton-like density. Alternatively, if the planet’s core actually contains more mass than expected, scientists say the atmosphere may have shrunk as the planet’s temperature cooled. timemeaning it would have appeared smaller than observed.
Now, using data from the James Webb Space Telescope – as well as previous observations from the Space Telescope Hubble Space Telescope Two independent teams of astronomers may have solved the mystery. In short, they discovered that the methane in the planet’s atmosphere is one-thousandth of what would be expected on this world. Because methane is unstable at high temperatures, astronomers say the surprisingly low amount is evidence that the gas deep inside the planet is “mixing vigorously with the cooler layers above.” David Singh The doctor from Johns Hopkins University (JHU) in Maryland, who led one of the two new studies, said in the statement. “The fact that we have detected so little, even though we have detected other carbon-bearing molecules, tells us that the interior of the planet must be much hotter than we thought.”
The researchers say the extra heat likely comes from the fact that WASP-107 b orbits its star every 5.7 days in an orbit that is not a perfect circle. The constant gravity of the star on WASP-107 b, which varies its distance from its star all the time, stretches and contracts the planet’s shape, thus heating it. On Earth, similar force the moon It causes high and low tides.
The planet’s hot core, combined with tidal heating from its star, also changes the chemistry of gases deep within the planet. Zafar Rustamkulova graduate student at JHU and co-author of one of the two new studies, said in an article statement from the University. “We believe that this heat causes gas chemistry to change, specifically the destruction of methane and the production of elevated amounts of carbon dioxide and carbon monoxide.”
In 2020, a team of astronomers, including Singh, discovered helium in the atmosphere of the planet WASP-107 b, marking the first time this gas has been observed on an exoplanet. The element was initially spotted around the world in 2018 before it existed there Certain Two years later, it was seen extending far into space as a faint cloud. Because the planet’s atmosphere is so sparse, astronomers say the ultraviolet radiation from WASP-107 b is slowly stripping the world of its air — about 0.1% to 4% of the mass of the atmosphere every billion years, to be specific. To the appearance of a comet. – Like a tail behind an orb.
Thanks to the planet’s extremely bloated nature, astronomers can look into its atmosphere about 50 times deeper than they can see on a world like Jupiter. Last year, for example, JWST observations of the atmosphere of the planet WASP-107 b showed that Rain sand On the planet.
This research is described in two studies Published Monday (May 20) in the journal Nature.