Discovery [1] | |
---|---|
Discovery date | May 10, 2017 |
Doppler spectroscopy (Transit) | |
Designations | |
EPIC 211945201 b | |
Orbital characteristics | |
0.148 AU | |
19.4921498(77) d [2] | |
Inclination | 87.9° |
Semi-amplitude | 5.7 m/s |
Physical characteristics | |
Mean radius | 0.546 RJ |
Mass | 0.085 MJ |
Temperature | 886.35 K |
K2-236b is a Neptune-like exoplanet that orbits an F-type star. It is also called EPIC 211945201 b. Its mass is 27 Earths, it takes 19.5 days to complete one orbit of its star, and is 0.148 AU from its star. Its discovery was announced in 2018. [3] This was the first exoplanet discovered by scientists based in India. The discoverers were Abhijit Chakraborty (PRL), Arpita Roy (Caltech), Rishikesh Sharma (PRL), Suvrath Mahadevan (Penn State), Priyanka Chaturvedi (Thüringer Landessternwarte Tautenburg), Neelam J.S.S.V Prasad (PRL), and B. G. Anandarao (PRL). [1]
The exoplanet K2-236b was discovered in 2018 using the transit method. Using this method, astronomers can see everything from methane to water vapor on other planets by photometry. [4] It is the only planet orbiting around EPIC 211945201, a G0 class star, situated in the constellation of Cancer in 596 light-years from the Sun. Its host star is aged 4 billion years. K2-236b orbits its star in about 19 terrestrial days. [5] It orbits closer to the star than the internal limit of the habitable zone. It has a low density and may be composed of gas.
K2-236b 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. [1]
The data shows that the
planet has a
radius of 6.12 ± 0.1 R⊕, and a
mass of 27+14
−12.6 M⊕. It consists of a
density of 0.65+0.34
−0.30 g/cm3. Based on the
mass and
radius, it estimates that the heavy element content is 60-70 % of the total
mass.
[1] The
surface temperature of the
planet was found to be around 776.35
K, as it is very close to the host
star.
[6] It is seven times nearer to its
star, in comparison with
Earth-
Sun
distance. This shows that the
extra-solar planet is in the uninhabitable zone. 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.