Who says you can’t lose your atmosphere in front of a red dwarf nearby and then grow a new one with the help of volcanic activity? Tits resistant the planet, located at 41 lightsyears from Earth, it seems to be thriving again after a rough encounter with the host star.
Exoplanet GJ 1132 b is both similar and very different from Earth. Sure, it’s a few times wider than our planet, but both worlds share similar densities and atmospheric pressures, and both appeared about 4.5 billion years ago. And like our planet, it started hot, with a hydrogen-rich atmosphere, and then gradually cooled.
However, the stories of these two planets are different.
While the Earth has always been a terrestrial, rocky world, GJ 1132 b began its life as a gas, Neptune-like planet. But, according to new research, a nearby red dwarf has erased its original atmosphere rich in hydrogen and helium with strong radiation, so GJ 1132 b, being stripped to its rocky core, is now technically a terrestrial planet. The new paper will appear in a future issue of the Astronomical Journal, but a prepress is available at arXiv.
The authors of this paper reached these conclusions based on direct observations of the exoplanet and theoretical modeling. The telescope chosen was Hubble Space Telescope, which allowed the team to identify the “secondary atmosphere”, which consists of molecular hydrogen, hydrogen cyanide, methane and an aerosol mist that resembles smog on Earth.
“It’s very interesting because we think the atmosphere we see now has been regenerated, so it could be a secondary atmosphere,” said Raissa Estrela, co-author of the study and a planetary scientist at NASA’s Jet Propulsion Laboratory. in Southern California, explained in a statement. “I thought at first that these highly irradiated planets could be quite boring because I thought they had lost their atmosphere. But we looked at the existing observations of this planet with Hubble and said, “Oh, no, there’s an atmosphere there.” ”
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As for an explanation, the authors say that much of the planet’s current hydrogen has been retained before, being absorbed into the mantle of molten magma. Volcanic processes are now causing this stored hydrogen to drain from below, feeding the new atmosphere, according to research.
“This process works early in a planet’s life, when the star is hotter,” said Mark Swain, a JPL scientist. the lead author of the study, in the NASA release. “Then the star cools and the planet just stays there. So you have this mechanism where you can cook from the atmosphere for the first 100 million years, and then things settle down. And if you can regenerate the atmosphere, maybe you can keep it. ”
GJ 1132 b, which requires only 1.5 days to make a complete orbit of its hungry host star, is probably prone to warming tides, in which gravitational forces overturn the inner planet. The exoplanet, despite its short year, is in an elliptical orbit, resulting in an effect known as “gravitational pumping”. As the GJ 1132 b swings back and forth, it alternates between crushing and stretching actions, producing an engine that drives tidal forces. and, in turn, preserving a liquid mantle.
The surface of this exoplanet is probably not very thick, maybe only a few hundred deep legs, according to the authors. The terrain is probably fairly flat, with cracks caused by the pumping actions of the tides, from which hydrogen flows constantly.
The new study has implications for the study of similar worlds elsewhere in the galaxy.
“The detection of an atmosphere on this rocky planet increases the possibility that the many highly irradiated super-terrestrial planets, considered to be the evaporated nuclei of the Sub-Neptunes, can, under favorable circumstances, host detectable atmospheres,” the study authors write.
The big question now is, how often does this happen? Is this just a strange appearance? That could be answered by the future James Webb Space Telescope, which, with its infrared capabilities, should be able to observe planets like this easily. Furthermore, JWST could also be used to study GJ 1132 b and to provide new data to confirm them. results.