TIC-320687387 B: a long-period eclipsing M-dwarf close to the hydrogen burning limit. Issue 2 (29th March 2022)

• Record Type: Journal Article
• Authors: Gill, Samuel; Ulmer-Moll, Solène; Wheatley, Peter J; Bayliss, Daniel; Burleigh, Matthew R; Acton, Jack S; Casewell, Sarah L; Watson, Christopher A; Lendl, Monika; Worters, Hannah L; Sefako, Ramotholo R; Anderson, David R; Alves, Douglas R; Bouchy, François; Bryant, Edward M; Eigmüller, Philipp; Gillen, Edward; Goad, Michael R; Grieves, Nolan; Günther, Maximilian N; Henderson, Beth A; Jenkins, James S; Mishra, Lokesh; Moyano, Maximiliano; Osborn, Hugh P; Tilbrook, Rosanna H; Udry, Stéphane; Vines, Jose I; West, Richard G
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 513:Issue 2(2022)
• Page Start: 1785
• Page End: 1793
• Publication Date: 2022-03-29
• Subjects: binaries: eclipsing; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stac798
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We are using precise radial velocities from CORALIE together with precision photometry from the Next Generation Transit Survey (NGTS) to follow-up stars with single-transit events detected with the Transiting Exoplanet Survey Satellite ( TESS ). As part of this survey, we identified a single transit on the star TIC-320687387, a bright ( T = 11.6) G-dwarf observed by TESS in Sectors 13 and 27. From subsequent monitoring of TIC-320687387 with CORALIE, NGTS, and Lesedi we determined that the companion, TIC-320687387 B, is a very low-mass star with a mass of $96.2 \pm _{2.0}^{1.9}$ M J and radius of $1.14 \pm _{0.02}^{0.02}$ R J placing it close to the hydrogen burning limit (∼80 M J ). TIC-320687387 B is tidally decoupled and has an eccentric orbit, with a period of 29.77381 d and an eccentricity of 0.366 ± 0.003. Eclipsing systems such as TIC-320687387 AB allow us to test stellar evolution models for low-mass stars, which in turn are needed to calculate accurate masses and radii for exoplanets orbiting single low-mass stars. The sizeable orbital period of TIC-320687387 B makes it particularly valuable as its evolution can be assumed to be free from perturbations caused by tidal interactions with its G-type host star.