(Daily News Scan - DNS English) Mini Neptune: Super Earth Having Sign of Life?
The astronomers and researchers are in continuous search of habitable planets apart from Earth. Various researches have been initiated along with sending space craft’s to study the atmosphere of different planets whether they are habitable or not. In a recent development, astronomers have found a potentially habitable exoplanet. It is twice more than the size of Earth. It has been named as K2-18b, located 124 light years away from Earth.
In this DNS we will look into details of this exoplanets and all the other necessary details.
K2-18b a new discovery of the astronomers is located 124 light years away from the Earth. It measures 2.6 times the radius and 8.6 times the mass of Earth. This exoplanet orbits its star within the habitable zone where the temperatures could allow liquid water to exist. This exoplanet had been in the news the previous year as well. At that time two different teams had detected water vapour in the planets hydrogen rich atmosphere.
The size of K2-18b makes it a smaller version of the Neptune. There have been several studies on different exoplanets till now. Even when water vapour is detected in the atmosphere of the exoplanets and if the exoplanet is in the habitable zone, that does not necessarily mean it has habitable conditions. It is important to acquire the combined understanding of the interior and atmospheric conditions of the planet and that too if the liquid water can or cannot exist beneath the atmosphere.
This exoplanet K2-18b was supposed to have a covering of hydrogen, surrounding a layer of high pressure water. It might have an inner core comprising of rock and iron. If the hydrogen covering is extremely thick, it will affect the temperature and pressure beneath the surface making it too good to support life. However after studying and researching, it has been found that despite the size of K2-18b, its hydrogen envelope is not too thick and the water layer might have the right conditions to support life.
This conclusion was brought through using the existing atmospheric observations, mass and radius of exoplanet. It determined its structure and composition. The atmosphere is rich with hydrogen along with a significant amount of water vapour. There were other chemicals such as methane and ammonia. The researcher’s team used the atmospheric properties as boundary conditions for models of the planetary interior to obtain the range of possible interior conditions. This included the extent of hydrogen envelope and the temperatures and pressures in the water layer. It was found that the maximum extent of hydrogen cover on the exoplanet is around 6 percent of its mass.
Now let us know few points about habitable zone and exoplanets.
Habitable Zone – It is the zone or area around a star where it is no too cold for liquid water to exist on the surface of the planet, neither is it too hot. This zone is also known as Goldilocks Zone.
Exoplanet –It is a planet outside the solar system. Planets that orbit around other stars are called exoplanet. Exoplanets are very hard to see directly with telescope. NASA has launched a spacecraft – KEPLER, to look for exoplanets.
