Priceton: Planetary Habitability Is Blowing in the Stellar Wind

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Priceton: Planetary Habitability Is Blowing in the Stellar Wind

Post by bystander » Thu Nov 30, 2017 5:16 pm

Blowing in the Stellar Wind
Princeton Plasma Physics Laboratory | 2017 Nov 30

Scientists reduce the chances of life on exoplanets in so-called habitable zones

Is there life beyond Earth in the cosmos? Astronomers looking for signs have found that our Milky Way galaxy teems with exoplanets, some with conditions that could be right for extraterrestrial life. Such worlds orbit stars in so-called “habitable zones,” regions where planets could hold liquid water that is necessary for life as we know it.

However, the question of habitability is highly complex. Researchers have recently raised doubts about water on — and thus potential habitability of — frequently cited exoplanets that orbit red dwarfs, the most common stars in the Milky Way.

In two papers in TheAstrophysical Journal Letters, the scientists develop models showing that the stellar wind — the constant outpouring of charged particles that sweep out into space — could severely deplete the atmosphere of such planets over hundreds of millions of years, rendering them unable to host surface-based life as we know it. ...

To broaden the picture, the first paper looks at the timescale of atmospheric retention on Proxima Centauri b (PCb), which orbits the nearest star to our solar system, some 4 light years away. The second paper questions how long oceans could survive on “water worlds” — planets thought to have seas that could be hundreds of miles deep. ...

Is Proxima Centauri b Habitable? A Study of Atmospheric Loss - Chuanfei Dong et al The Dehydration of Water Worlds via Atmospheric Losses - Chuanfei Dong et al
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