In 2013, astronomer Mikko Tuomi first discovered the closest habitable Zone planet in Centaurus constellation. This known exoplanet is pretended to be the habitable Zone planet and is called Proxima Centaury B.
Proxima Centaury B is orbiting in the potential habitable Zone of the Sun’s closest star, Proxima Centauri. Proxima Centauri is actually an M-dwarf Star. It’s located around 4.28 light years away from The sun. Moreover, the mass of this M-dwarf is one tenth of the Sun.
However, the estimated mass of Proxima Centauri B is around 1.3 times that of the Earth. As this exoplanet orbiting around a low mass M-dwarf star then it’s orbiting closer to its host star than Earth. This is because the M-dwarf star has dim luminosity than the Sun, around one thousand less luminous. That’s why the habitable zone of Proxima Centauri is closer than the solar system.
According to the news portal of Smithsonian Astrophysical Observatory, the orbital period of Proxima Centauri B is around 11.3 days. However, this close habitable zone around host star results in an adverse effect on the planet’s atmosphere in that Zone. This is because the M-dwarf star radiates large proportion than the Sun.
Most of the radiation comes from M-dwarf in the form of UV, extreme UV, and X-rays. So, this radiation can evaporate a planet's atmosphere, especially when those planets orbit nearby in the habitable zone. So the biggest question is, whether the climate of Proxima Centauri B is really habitable or not.
In addition, star's magnetic activity not only cause high radiation but also drives stellar winds and coronal mass ejections. Both are perilous for survivability in Proxima Centauri B’s atmosphere. However, astronomer Cecilia Garraffo has built a program to model the stellar winds and magnetic field for active M-dwarf stars. They also published the detailed studies in the journal of Cornell University Library.
According to study, they estimated the pressure of the stellar wind in Proxima Centauri B. Surprisingly, it is thousand to ten thousand times higher than the solar wind pressure at Earth. Furthermore, the pressure is non-uniform and the atmosphere of Proxima Centauri B also likely to experience supersonic wind conditions. However, researchers need further studies about other exo-planets around the M-dwarf star to find the exact answer about planet’s atmosphere.
