EPIC 219945201 b, also known as K2-236 b, is a Neptune-like extrasolar planet orbiting the G0 type star EPIC 211945201. The mass of this planet is about 0.085 of Jupiter's mass, or 27 Earths. The planet takes around 19.5 days to complete an orbit of its star, and is around 0.148 AU away from the star. The discovery of the planet was announced in 2018. This was the first extrasolar planet to be discovered by scientists at the Physical Research Laboratory in Ahmedabad, India.
Overview[]
The planet was discovered on May 10, 2017 and was announced in 2018, using the transmit method. Using this method, astronomers and scientists are able to see everything from methane to water vapor on other planets by photometry. It is currently the only known planet that orbits the star EPIC 211945201, a G0 class star around 595 light years away from Earth in the constellation Cancer. The star is estimated to be around 4 billion years old. EPIC 211945201 b orbits its star around every 19.5 Earth days. The Earth similarity index of the planet is rated as 0.14.
Discovery[]
EPIC 211945201 b was found to be a planetary candidate from K2 photometry in Campaigns 5 & 16. The exoplanet transits the bright star (Vmag = 10.15, G0 spectral type) in a 19.492 day orbit. The photometric data combined with false positive probability calculations using VESPA may not be sufficient to confirm the planetary scenario but high-resolution spectroscopic are taken using the PARAS spectrograph (19 radial velocity observations) over a time-baseline of 420 days.
The data shows that the planet has a radius of 6.12 Earth radius, and a mass of ~27 Earth mass. It consists of a density of 0.65 g/cm3. Based on the mass and radius, it estimates that the heavy element content is 60-70% of the total mass. The surface temperature of the planet is estimated to be around 886.35 K as it is very close to the host star. The 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 scientists.