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.
Original language | English (US) |
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Pages (from-to) | 4684-4701 |
Number of pages | 18 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 505 |
Issue number | 4 |
DOIs | |
State | Published - Aug 1 2021 |
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
Keywords
- planetary systems
- planets and satellites: atmospheres
- planets and satellites: composition
- planets and satellites: individual: TOI-1260b, c
- stars: low-mass
- techniques: photometric
- techniques: radial velocities