The NASA team discovered an exoplanet that created a second atmosphere on its own after losing its original atmosphere due to radiation from its host star.
The researchers analyzed Hubble Space Telescope observations collected in 2017 around the planet GJ 1132 b. The planet orbits in a narrow orbit around the red dwarf star 41 light years from Earth, completing one revolution in 1.5 days and absorbing a lot of stellar radiation in the process. The team detected signs of a second atmosphere produced by the exoplanet itself.
“The discovery is extremely exciting because we believe the atmosphere we are seeing is regenerated, which means it could be a second atmosphere,” said study co-author Raissa Estrela. , exoplanet scientist at NASA’s Jet Propulsion Laboratory (JPL) in California. “Initially, we thought that planets with high radiation might be quite boring because they lost their atmosphere. But we looked at previous observations of GJ 1132b with the Hubble Telescope and were amazed to know that there is an atmosphere there “.
The loss of atmosphere could create a planet the size of Earth but with a very different history from ours. Researchers believe that after GJ 1132 lost its atmosphere rich in hydrogen and helium, it became a barren world. But Hubble’s observations show that GJ 1132b is now blanketed in a mixture of hydrogen, hydrogen cyanide, methane, and aerosol-rich smog like Earth mist.
To find out what’s going on in the system, the team focused on the relationship between GJ 1132 and the host star. One side of an exoplanet always faces its host star, much like the Moon orbits the Earth. But in this case, the star’s attraction for GJ 1132 b is so strong that it heats the planet a lot. The result could be frequent volcanic activity.
The atmosphere could then form from gas escaping from molten rock on the planet. In particular, the team describes GJ 1132 b as a world covered with a thin shell with many eggshell-shaped cracks. The cracks, generated by the host star’s gravity, allow gas to escape, creating a second atmosphere. The researchers hope that NASA’s powerful space telescope James Webb, scheduled to launch this fall, will help them observe the surface of GJ 1132b in infrared light. The results of the study will be published in the Astronomical Journal.
