2021/05/05 by Nora L. Eisner, Belinda Nicholson, Belinda A. Nicholson +61 · 11 citations
Physics and Astronomy · #Astro and Planetary Science #Astrobiology #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Dwarf planet #Exoplanet #Physics #Planet #Planetary system #Stellar, planetary, and galactic studies #astro-ph.EP
paper · pdf · doi:10.1093/mnras/stab1253
published in Monthly Notices of the Royal Astronomical Society 505(2), 1827-1840 (Oxford University Press) · Accepted for publication in MNRAS (15 pages, 10 figures, 3 tables)
openalex publication_date 2021/05/05 · arxiv created 2021/06/08 · arxiv updated 2021/06/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
ABSTRACT We report on the discovery and validation of a two-planet system around a bright (V = 8.85 mag) early G dwarf (1.43 R⊙, 1.15 M⊙, TOI 2319) using data from NASA’s Transiting Exoplanet Survey Satellite (TESS). Three transit events from two planets were detected by citizen scientists in the month-long TESS light curve (sector 25), as part of the Planet Hunters TESS project. Modelling of the transits yields an orbital period of 11.6264 - 0.0025 ^ + 0.0022 d and radius of 3.41 - 0.12 ^ + 0.14 R⊕ for the inner planet, and a period in the range 19.26–35 d and a radius of 5.83 - 0.14 ^ + 0.14 R⊕ for the outer planet, which was only seen to transit once. Each signal was independently statistically validated, taking into consideration the TESS light curve as well as the ground-based spectroscopic follow-up observations. Radial velocities from HARPS-N and EXPRES yield a tentative detection of planet b, whose mass we estimate to be 11.56 - 6.14 ^ + 6.58 M⊕, and allow us to place an upper limit of 27.5 M⊕ (99 per cent confidence) on the mass of planet c. Due to the brightness of the host star and the strong likelihood of an extended H/He atmosphere on both planets, this system offers excellent prospects for atmospheric characterization and comparative planetology.