Publication Date:
2020-07-17
Description:
We present an independent discovery and detailed characterization of K2-280 b, a transiting low density warm sub-Saturn in a 19.9-d moderately eccentric orbit (e = $0.35_{-0.04}^{+0.05}$ ) from K2 campaign 7. A joint analysis of high precision HARPS, HARPS-N, and FIES radial velocity measurements and K2 photometric data indicates that K2-280 b has a radius of Rb = 7.50 ± 0.44 R⊕ and a mass of Mb = 37.1 ± 5.6 M⊕, yielding a mean density of ρb = $0.48 _{ - 0.10 } ^ { + 0.13 }$ ${
m g, cm^{-3}}$. The host star is a mildly evolved G7 star with an effective temperature of Teff = 5500 ± 100 K, a surface gravity of $log , g_{star }$ = 4.21 ± 0.05 (cgs), and an iron abundance of [Fe/H] = ${0.33}, {pm }, {0.08}$ dex, and with an inferred mass of M⋆ = 1.03 ± 0.03 M⊙ and a radius of R⋆ = 1.28 ± 0.07 R⊙. We discuss the importance of K2-280 b for testing formation scenarios of sub-Saturn planets and the current sample of this intriguing group of planets that are absent in the Solar system.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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