TOI-954 b and K2-329 b: Short-period Saturn-mass Planets that Test whether Irradiation Leads to Inflation
Abstract
We report the discovery of two short-period Saturn-mass planets, one transiting the G subgiant TOI-954 (TIC 44792534, V = 10.343, T = 9.78) observed in TESS sectors 4 and 5 and one transiting the G dwarf K2-329 (EPIC 246193072, V = 12.70, K = 10.67) observed in K2 campaigns 12 and 19. We confirm and characterize these two planets with a variety of ground-based archival and follow-up observations, including photometry, reconnaissance spectroscopy, precise radial velocity, and high-resolution imaging. Combining all available data, we find that TOI-954 b has a radius of ${0.852}_{-0.062}^{+0.053}\,{R}_{{\rm{J}}}$ and a mass of ${0.174}_{-0.017}^{+0.018}$ MJ and is in a 3.68 day orbit, while K2-329 b has a radius of ${0.774}_{-0.024}^{+0.026}\,{R}_{{\rm{J}}}$ and a mass of ${0.260}_{-0.022}^{+0.020}$ MJ and is in a 12.46 day orbit. As TOI-954 b is 30 times more irradiated than K2-329 b but more or less the same size, these two planets provide an opportunity to test whether irradiation leads to inflation of Saturn-mass planets and contribute to future comparative studies that explore Saturn-mass planets at contrasting points in their lifetimes.
- Publication:
-
The Astronomical Journal
- Pub Date:
- February 2021
- DOI:
- 10.3847/1538-3881/abd187
- arXiv:
- arXiv:2010.14436
- Bibcode:
- 2021AJ....161...82S
- Keywords:
-
- Exoplanet systems;
- Photometry;
- Transit photometry;
- Spectroscopy;
- High resolution spectroscopy;
- RV;
- G stars;
- G dwarf stars;
- G subgiant stars;
- Hot Jupiters;
- 484;
- 1234;
- 1709;
- 1558;
- 2096;
- 1332;
- 558;
- 556;
- 560;
- 753;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 28 pages, 9 figures, 11 tables, accepted by AJ, ancillary data also available at https://github.com/vulpicastor/toi954-data