Hot planets around cool stars – two short-period mini-Neptunes transiting the late K-dwarf TOI-1260
Author(s)
Matthews, Elisabeth C; Levine, Alen M.; Ricker, George R; Seager, Sara; Vanderspek, Roland K
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<jats:title>ABSTRACT</jats:title>
<jats:p>We present the discovery and characterization of two sub-Neptunes in close orbits, as well as a tentative outer planet of a similar size, orbiting TOI-1260 – a low metallicity K6 V dwarf star. Photometry from Transiting Exoplanet Survey Satellite(TESS) yields radii of Rb = 2.33 ± 0.10 and Rc = 2.82 ± 0.15 R⊕, and periods of 3.13 and 7.49 d for TOI-1260 b and TOI-1260 c, respectively. We combined the TESS data with a series of ground-based follow-up observations to characterize the planetary system. From HARPS-N high-precision radial velocities we obtain Mb = $8.6 _{ - 1.5 } ^ { + 1.4 }$ and Mc = $11.8 _{ - 3.2 } ^ { + 3.4 }$ M⊕. The star is moderately active with a complex activity pattern, which necessitated the use of Gaussian process regression for both the light-curve detrending and the radial velocity modelling, in the latter case guided by suitable activity indicators. We successfully disentangle the stellar-induced signal from the planetary signals, underlining the importance and usefulness of the Gaussian process approach. We test the system’s stability against atmospheric photoevaporation and find that the TOI-1260 planets are classic examples of the structure and composition ambiguity typical for the 2–3 R⊕ range.</jats:p>
Date issued
2021Department
Massachusetts Institute of Technology. Department of Physics; MIT Kavli Institute for Astrophysics and Space Research; Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences; Massachusetts Institute of Technology. Department of Aeronautics and AstronauticsJournal
Monthly Notices of the Royal Astronomical Society
Publisher
Oxford University Press (OUP)