In a recent study published in The Astrophysical Journal Letters, an international team of researchers led by the University of Kansas examined a super-Earth exoplanet, GJ 1252b, which orbits an M-dwarf star approximately 66 light-years from Earth, discovering that it does not house a significant atmosphere. This study holds the potential to help us better understand the formation and evolution of exoplanets, specifically those close to the size of Earth.
"The pressure from the star's radiation is immense, enough to blow a planet's atmosphere away," said Michelle Hill, who is a PhD Candidate at the University of California Riverside, and a co-author on the study.
M-dwarf stars are much smaller than our own Sun but are far more numerous, with estimates putting them at 10 times as many M-dwarf stars than our own Sun. It is because of this that they have become a favorite in the search for life beyond Earth. However, this most recent discovery might put a damper on finding life around these stars, as the findings could indicate there are more exoplanets orbiting these types of stars that also lack an atmosphere, and possibly life.
"It's possible this planet's condition could be a bad sign for planets even further away from this type of star," Hill said. "This is something we'll learn from the James Webb Space Telescope, which will be looking at planets like these."
While Gj 1252b is slightly larger than Earth, it also orbits exceptionally close to its parent star, completing two orbits during the course of one day on Earth. This means the planet is insanely hot, along with possibly being inhospitable, making it more of a Mercury-analog than Earth.
"If a planet is far enough away from an M dwarf, it could potentially retain an atmosphere. We cannot conclude yet that all rocky planets around these stars get reduced to Mercury's fate," Hill said. "I remain optimistic."
Sources: The Astrophysical Journal Letters, Scientific American
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