In a first, Indian team discovers an exoplanet

NEWDELHI: A team of scientists has become the first Indians to discover an exoplanet. Led by Abhijit Chakraborty of the Physical Research Laboratory (PRL) in Ahmedabad, the scientists have found a planet that is 600 light years from Earth.

The newly discovered planet is called EPIC 211945201b or K2-236b.

It is estimated to be 27 Earth mass and its size is about 6 Earth radii, according to the Indian Space Research Organisation (Isro).

While planets revolve around a sun, exoplanets orbit stars. The first exoplanet discovery was confirmed in 1992.

Chakraborty and his team had been studying data on the light emitted by a star called EPIC 211945201 or K2-236 for the past year-and-a-half. They did not directly observe the planet, but monitored changes in the wavelength of the light emitted by the host star and deduced the presence of another body in its star system.

“There is a lot of serendipity involved,” said Chakraborty. “You are looking at thousands and thousands of stars and you do not know if a star has a planet around it. You look for signs that there are transitory bodies around the star. We seriously

looked at hundreds of stars.”

The body emerged as a planetary candidate based on data from NASA’S Kepler 2 mission, which showed the planet came between the observer on earth and the host star.

“We followed this body for oneand-a-half years, one has to be sure what one is observing.” Chakraborty said. Since the Kepler 2’s photometry could not confirm the body was a planet, the team measured its mass using the PRL Advance Radial-velocity Abu-sky Search” (PARAS), a precise and high resolution spectrograph that was integrated with the 1.2m Telescope at PRL’S Gurushikhar Observatory in Mount Abu, Rajasthan.

One reason that exoplanets have become areas of active research is the search for a planet that can support life the way Earth does.

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