Water vapor detected in the atmosphere of an exoplanet. Can K2-18b be a potential habitable super Earth?
Hello earthlings, believe it or not (that goes to flatminded) science has reached a certain level that enables us to explore the universe, searching even for the existence of other life forms out there. In that way, researchers scanning the vast space with telescopes, spectrographs and any other available technology for signs that can give them a leading way to confirm the potential existence of any life form out of this planet.
There are many factors that science community set to be that possible, one of those is the existence of water, because the water is essential for life as we know it. It's not the first time that astronomers find sings of water on exoplanets, something that's already amazing, but it seems that this time, they found something extraordinary. They they’ve detected water vapor in the atmosphere of an Earth like planet called K2-18b, with mass eight times that of Earth and radius 2.7 that of Earth, this Super Earth planet orbiting it's star habitable zone, at distance that water can exist in liquid form!
Being more specific, K2-18b also known as EPIC 201912552 b discovered back on 2015 along with over 1200 exoplanets during the "Second Light" K2 mission" a Kepler space telescope program! In 2017 data by Spitzer Space Telescope confirmed that K2-18b orbits it star (the red dwarf K2-18) in the habitable zone around a period time of 33 days and located within the constellation of Leo, but outside its lion asterism!
It was initially considered a mini-Neptune on its 2015 discovery, because of it's mass (8.63±1.35 that of Earth with mini-Neptunes having up to 10 Earth masses ) and it's thick hydrogen–helium atmosphere, but later has classified as a super-Earth.
According to first author Dr Angelos Tsiaras (UCL Centre for Space Exochemistry Data (CSED))
Here, we report the detection of a spectroscopic signature of water in the atmosphere of K2-18 b—a planet of eight Earth masses in the habitable zone of an M dwarf7—with high statistical confidence (Atmospheric Detectability Index5 = 5.0, ~3.6σ (refs. 8,9)). In addition, the derived mean molecular weight suggests an atmosphere still containing some hydrogen.
It's the first time ever that water found on a planet orbiting at habitable zone of it's star that has also an atmosphere and closed to earth standards temperatures, so yes, right now is the best candidate to support life as we know it!
That doesn't mean that it can be habitable by humans, first of all it may be close enough astronomical (111 Light years) but is far away from what are we capable to cover with our current technology. Secondly, the planets gravity is almost twice that of earth whatever that means. And last but not least, it's orbiting a red Dwarf, red Dwarfs are know for their high activity and it's more unstable causing some times flare explosions that doubling their brightness in minutes, in addition they emitting most of their energy as ultraviolet light, while at least the earth's plants make the most use of visible light, as ultraviolet light photons carry very little energy to serve photosynthesis.
Facts
Red Dwarfs make up the vast majority of the stars in our Galaxy, and probably the Universe, but it's not the stars that can be looked with naked eye in the sky because they are very dim.
They are the longest living "stars" (not "stellar corpses" such as white dwarfs and neutron stars), their potential lifespan is many times greater than the current age of the Universe itself!
Of the 350 stars that are less than 10 parsecs from us (32.6 light years), about 70% are red dwarfs, while it is estimated that over 100 other stars in the same area have not yet been discovered and are all almost red dwarfs.
Considering all the above, K2-18b it couldn't be a "habitable super Earth" , but it's the best candidate to support life from the already known planets!
