The most common type of star in the universe, an M dwarf, appears to have no atmosphere at all. A shift in the search for life on other planets is likely to be caused by this discovery.
A large number of planets are unlikely to harbor living things because they lack atmospheres.
The Astrophysical Journal Letters detail the work that led to the discovery of GJ 1252b.
During a single day, this planet goes around its star twice. GJ 1252b is much closer to its star than Earth is to the sun, which makes it extremely hot and inhospitable.
The atmosphere of a planet can be blown away by the star's radiation.
volcanic emissions and other carbon cycling processes help replenish the atmosphere that is lost by the sun. In closer proximity to a star, a planet can't replenish the amount that's been lost.
This is the fate of Mercury. The atmosphere is made up of atoms that are blasted off by the sun. The atoms escape into space when the planet is very hot.
Astronomers used a secondary eclipse to determine that GJ 1252b does not have an atmosphere. This type of eclipse happens when a planet passes behind a star and the light from it is blocked.
The planet's daytime temperatures are so hot that gold, silver, and copper will all melt on datememe. Researchers believed there was no atmosphere because of the heat and low surface pressure.
The researchers concluded GJ 1252b wouldn't be able to hold on to an atmosphere even with a lot of carbon dioxide. It wouldn't have an atmosphere if the planet had 700 times as much carbon as Earth. Stephen Kane is an astronomer and study co-author.
M dwarf stars have more flares and activity than the sun, which makes them less likely to hold onto their atmospheres.
This planet's condition could be a bad sign for planets further away from this type of star. It's something we'll learn from the James Webb Space Telescope, which will be looking at planets like these.
This project was supported by a grant from the Future Investigators in NASA Earth and Space Science and Technology program.
Most of the stars in the solar neighborhood are M dwarfs. Even if planets are ruled out completely, there are still hundreds of stars similar to the sun that could be suitable for life.
If a planet is close to an M dwarf, it might retain an atmosphere. We don't know if rocky planets around these stars get reduced to Mercury's fate. I'm still optimistic.
More information: Ian J. M. Crossfield et al, GJ 1252b: A Hot Terrestrial Super-Earth with No Atmosphere, The Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/ac886b Journal information: Astrophysical Journal Letters
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