Evidence of a Sub-Saturn around EPIC 211945201

Abhijit Chakraborty, Arpita Roy, Rishikesh Sharma, Suvrath Mahadevan, Priyanka Chaturvedi, Neelam J.S.S.V. Prasad, B. G. Anandarao

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Abstract

We report here strong evidence for a sub-Saturn around EPIC 211945201 and confirm its planetary nature. EPIC 211945201b was found to be a planetary candidate from K2 photometry in Campaigns 5 and 16, transiting a bright star (V mag = 10.15, G0 spectral type) in a 19.492 day orbit. However, the photometric data combined with false positive probability calculations using VESPA was not sufficient to confirm the planetary scenario. Here, we present high-resolution spectroscopic follow up of the target using the PARAS spectrograph (19 radial velocity observations) over a time baseline of 420 days. We conclusively rule out the possibility of an eclipsing binary system and confirm the 2σ detection of a sub-Saturn planet. The confirmed planet has a radius of 6.12 ±0.1 R , and a mass of . We also place an upper limit on the mass (within the 3σ confidence interval) at 42 M above the nominal value. This results in the Saturn-like density of . Based on the mass and radius, we provide a preliminary model-dependent estimate that the heavy element content is 60%-70% of the total mass. This detection is important as it adds to a sparse catalog of confirmed exoplanets with masses between 10 and 70 M and radii between 4 and 8 R , whose masses and radii are measured to a precision of 50% or better (only 23 including this work).

Original languageEnglish (US)
Article number3
JournalAstronomical Journal
Volume156
Issue number1
DOIs
StatePublished - Jul 2018

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Chakraborty, A., Roy, A., Sharma, R., Mahadevan, S., Chaturvedi, P., Prasad, N. J. S. S. V., & Anandarao, B. G. (2018). Evidence of a Sub-Saturn around EPIC 211945201. Astronomical Journal, 156(1), [3]. https://doi.org/10.3847/1538-3881/aac436