Scientists at the Physical Research Laboratory (PRL), Ahmedabad, have discovered a new planet that is 27 times the mass of the Earth and six times its radius. The planet, scientifically known as an exoplanet since it is situated beyond our own solar system, is located 600 light years away.
A report on the website of the Indian Space Research Organisation (ISRO) said that the discovery was made by measuring its mass using the indigenously-designed “PRL Advance Radial-velocity Abu-sky Search” (PARAS) spectrograph. PARAS is integrated with a 1.2m Telescope at PRL’s Gurushikhar Observatory in Mount Abu, Rajasthan.
The name of the host star is EPIC 211945201 or K2-236. Hence the new planet that revolves around a sun-like star will be known as EPIC 211945201b or K2-236b, said ISRO.
With this discovery, India has joined a handful of countries which have discovered planets around stars. Very few such spectrographs exist around the world that can do such precise measurements, said ISRO. Such facilities are located mostly in the United States and Europe.
How The New Planet Was Found
Scientists began exploring the possibility of a new planet after coming across photometry data (indicating the brightness levels of a star) from the NASA K2 (Kepler 2) space observatory. It showed that a source that could be a planet body was coming between a star and the Earth as it went around, therefore blocking a tiny amount of star-light.
Its size was calculated by measuring the amount of light that it was blocking while going around the star. The photometric data was not, on its own, enough to conclude that this was indeed a new planetary system.
This is where the Indian scientists from PRL came into the picture. They used the PARAS spectrograph to study the nature of this system over a time-baseline of 420 days in 1.5 years. Having calculated the mass and the radius of this new planet, the scientists also determined that nearly 60-70% of it was made up of heavy elements like ice, silicates, and iron.
Due to its mass and composition, the new planet has been classified as sub-Saturn or super-Neptune. It takes 19.5 earth days to revolve around the parent star.
Its surface temperature was found to be as high as 600 degrees Celsius, since it is located very close to the star, about seven times less than the Earth-Sun distance. This extreme temperature might make the planet uninhabitable but ISRO pointed out that “such a discovery is of importance for understanding the formation mechanism of such super-Neptune or sub-Saturn kind of planets that are too close to the host star”.
According to ISRO, only 23 such systems (including the latest one) are known till now with such precise measurement of mass and radii.