K2-236b: Indian Scientists Discover Planet 600 Light Years Away (Download PDF)


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Team of scientists from Physical Research Laboratory (PRL), Ahmedabad, discovered sub-Saturn or super-Neptune size exoplanet, which is about 27 times mass of Earth & 6 times radius of Earth.

Image of Planet 600 light years away

Image of Planet 600 Light Years Away

Image of Planet 600 light years away

  • Exoplanet was found around Sun-like star & goes around star in abt 19.5 days. Host star is about 600 light years away from Earth.

  • Name of host star around new planet is EPIC 211945201 or K2 - 236, planet will be known as EPIC 211945201b or K2 - 236b.

  • Scientists found that surface temp. of the planet is around 600 degrees Celsius given fact that it is very close to host star- new planet is 7 times nearer to host star than earth.

  • Indian scientists at PRL, Ahmedabad, found new planet K2 - 236b to be 6 Earth radii.

  • New planet will help understand formation mechanism of such super-Neptune or sub-Saturn kind of planets.

PRL Advance Radial-velocity Abu-sky Search (PARAS) Spectrograph

  • Host star is about 600 light years away from Earth. Discovery of new planet was made by measuring mass of planet using indigenously designed “PRL Advance Radial-velocity Abu-sky Search” (PARAS) spectrograph.

  • PARAS spectrograph was integrated w/1.2m telescope at PRL’s Gurushikhar Observatory in Mount Abu, India.

  • Only few spectrographs that can do such precise measurements exist around world & mostly are found in USA & in Europe.

  • PARAS is 1st of its kind spectrograph in India. It can measure mass of planet going around star & w/this latest feat, India has joined club of only few countries that have discovered planets around stars.

What is Spectrograph?

  • Spectrograph separates and measures the wavelengths present in Electromagnetic radiation. It also measures the relative amounts of radiation at each wavelength.

How Are Planets Discovered?

  • Source was found to be planetary candidate from NASA K2 (Kepler2) photometry because it was transiting.
  • When planet body comes in b/w star & observer on Earth as it goes around star, it blocks tiny amount of star-light.
  • By measuring amount of light blocked by planet body, scientists can measure diameter or size of planet.
Image of process of Planets Discovered

Image of Process of Planets Discovered

Image of process of Planets Discovered

Hurdles & PARAS Spectograph

  • Independent measurement of mass of body was necessary for discovery, which was made by PARAS spectrograph.
  • Gravitational pull caused by planet on its host star makes it wobble around their common centre of mass.
  • Gravitational pull shifts spectra & can be measured in terms of Radial Velocity using precise & stabilised High Resolution Spectrographs, like PARAS.
  • PRL scientists observed target over time-baseline of 420 days, 1.5 years, using PARAS spectrograph for probing nature of system.
  • Model shows wobbling of host star & its amplitude gives us mass of exoplanet K2 - 236b.
  • Model-dependent calculations suggest that heavy elements, like ice, silicates, & iron content is 60 - 70 % of total mass.


  • Last year, team of Indian astronomers discovered massive supercluster of galaxies. Saraswati - supercluster of galaxies is as big as 20 million billion suns.
  • According to Pune-based Inter University Centre for Astronomy & Astrophysics (IUCAA), Saraswati is one of largest known structures in neighbourhood of universe.
  • It is 4, 000 million light-years away from Earth & roughly more than 10 billion years old.

Physical Research Laboratory (PRL), Ahmedabad

  • Founded in – 1947
  • Known as cradle of Space Sciences in India

- Published/Last Modified on: August 31, 2018

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