Red dwarfs are some of the smallest stars. These stars are usually also relatively young, as they have a long lifespan. Planets around red dwarfs are much closer to it. Red dwarf star planets might lose oxygen because of the star's effects on it.
Astronomers look for planets at a star's habitable zone. This area around the star is where life would most likely form. A small star like a red dwarf will have its habitable zone much closer to it than the Earth's distance is to the Sun.
The closeness of a planet to its parent star could be an issue though. Red dwarfs might be cooler than the Sun, but they are also more volatile. William Danchi, co-author of the study and an astronomer at NASA Goddard Space Flight Center, has said that red dwarfs have frequent solar stellar eruptions. These eruptions have the capability of stripping away a planet's atmosphere.
Planets closer to the star would be more vulnerable to stellar eruptions. This would be an issue for planets that are around a red dwarf. These super flares are emitted by red dwarfs on a daily basis. The super flares can be powerful, and some are 10 times more powerful than those on the Sun, according to NASA.
The stellar flares and x-rays coming from red dwarfs can extend to the habitable zones of the stars, as explained by lead author and solar scientist Vladimir Airapetan. The stellar flares have x-rays that break molecules into atoms. In this way, oxygen and hydrogen in a planet's atmosphere drift off into space.
As more x-rays are emitted from red dwarfs, more hit a planet and then more oxygen atoms escape. In just a few million years, a planet can become uninhabitable because of this, as Science Daily reports. Any water supply on the planet would disappear as well because of this.
This could be experienced by the latest exoplanet discovered. Proxima b is around a red dwarf, and its closeness to its star might make it uninhabitable soon. Researchers estimate that it is always under extreme radiation from stellar flares every two hours. That would mean any atmosphere that it has would soon be gone in just ten million years.
Astronomers are excited about finding new planets. However, not all planets could be inhabited even if they are within the habitable zone. Red dwarf star planets might lose oxygen because of their closeness to their stars. Astronomers also have a theory about disappearing ice volcanoes on Ceres.
