New Evidence Shows Proxima B Could Really Be Habitable
As the nearest star in this solar system, Proxima Centauri has been of interest to astronomers since it was discovered about a century ago. The significance of it grew even more when a small rocky exoplanet was found orbiting it: Proxima b.
According to a report from Space, new evidence was uncovered recently, supporting the theory that Proxima b is actually fit for life. The recent study revealed that there is now very strong evidence of Proxima Centauri being gravitationally bound to the Alpha Centauri system. This would make Alpha Centauri a triple-star system, with Alpha Centauri A and B, then Proxima b orbiting at a further distance and wider berth.
Astronomers Pierre Kervella, Frédéric Thévenin and Christophe Lovis spearheaded the research, a report from the European Southern Observatory (ESO) revealed. They used an ultra-sensitive instrument called the High Accuracy Radial Velocity Planet Searcher (HARPS) at the ESO's La Silla Observatory in Chile to observe the radial velocity of Proxima Centauri, particularly in relation to Alpha Centauri. The HARPS is able to detect the slight wobble of stars due to exoplanets pulling at them gravitationally -- it was actually the instrument that was able to detect the existence of Proxima b.
This time, HARPS observed the velocity that Proxima Centauri is moving away from the Earth and compared it to the radial velocity of Alpha Centauri. The two numbers match, indicating that the star likely has a wide orbit around Alpha Centauri and that they are most likely bound in gravity.
If this is true, then Proxima Centauri and Alpha Centauri were probably formed by the same nebulla billions of years ago, and they are likely the same age. Because Proxima Centauri was ejected from the binary, the researchers theorize that a planet was formed far from the star and then moved to a lower orbit.
Since it was located at a far and likely cold orbit, this planet would probably be icy -- and ice could have been water. Now that Proxima b's place in the galaxy is habitable for water, it's possible that water still exists on its surface at present.