It started in August – When enthusiastic astronomers discovered a new exoplanet – Proxima b – it is reminiscent of Earth and orbits the Sun’s nearest neighbor star, Proxima Centauri which is “only” 4.2 light years from earth. At first it looked like Proxima b had a surface covered in stone, but now French researchers from Marseille Astrophysics Laboratory in France looked a little closer at how habitable it is. The researchers made simulations of possible planetary radii, which they believe may be between 0.94 and 1.4 times the Earth’s radius.
More water than on Earth – Their calculations show that if the planet has the largest possible radius of 8 920 km it may mean that it has a gigantic ocean of liquid water up to 200 kilometers deep. The minimum radius, approximately 6 000 km, would mean that the planet is very compact and has a sea corresponding to 0.05 percent of the planet’s total mass which may not sound much, but in comparison, Earth’s oceans are approximately 0.02 percent of it’s total mass. All the simulations the researchers have done so far show that the planet has an ocean of liquid water.
Good odds for life – So far, the researchers have been cautious when considering life on Proxima b because the planet circles very close to its star – only 7.4 million kilometers from Proxima Centauri. In comparison, Mercury – which is the planet closest to the sun in our solar system is about ten times farther away in its orbit and has a temperature of up to 427 degrees Celsius. But because Proxima Centauri only shines 0.1 percent as bright as the sun, the temperature should be more “human” on Proxima b than on Mercuri. You can read more in-depth material about the discovery, Proxima Centauri and the exoplanet Proxima b on NASA’s website here