Hot planets around cool stars - two short-period mini-Neptunes transiting the late K-dwarf TOI-1260
Abstract
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.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- August 2021
- DOI:
- 10.1093/mnras/stab1464
- arXiv:
- arXiv:2104.05653
- Bibcode:
- 2021MNRAS.505.4684G
- Keywords:
-
- techniques: photometric;
- techniques: radial velocities;
- planets and satellites: atmospheres;
- planets and satellites: individual: TOI-1260b;
- c;
- planets and satellites: composition;
- stars: low-mass;
- planetary systems;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- doi:10.1093/mnras/stab1464