Five new eclipsing binaries with low-mass companions

¹ Astronomical Institute, Academy of Sciences, Fričova 298, 251 65 Ondřejov, Czech Republic
² Astronomical Institute, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 180 00 Praha 8, Czech Republic
³ Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany
⁴ Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotlářská 267/2, 611 37 Brno, Czech Republic
⁵ Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife, Spain
⁶ Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain
⁷ Nordic Optical Telescope, Rambla José Ana Fernández Pérez 7, 38711 Breña Baja, Spain
⁸ NSF’s National Optical-Infrared Astronomy Research Laboratory, 950 N. Cherry Ave., Tucson, AZ 85719, USA
⁹ Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
¹⁰ Dipartimento di Fisica, Università di Torino, Via P. Giuria 1, 10125 Torino, Italy
¹¹ Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala, Sweden
¹² Astronomy Department and Van Vleck Observatory, Wesleyan University, Middletown, CT 06459, USA
¹³ Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark

Received: 19 March 2024
Accepted: 6 June 2024

Abstract

Precise space-based photometry from the Transiting Exoplanet Survey Satellite results in a huge number of exoplanetary candidates. However, the masses of these objects are unknown and must be determined by ground-based spectroscopic follow-up observations, frequently revealing the companions to be low-mass stars rather than exoplanets. We present the first orbital and stellar parameter solutions for five such eclipsing binary-star systems using radial-velocity follow-up measurements together with spectral-energy-distribution solutions. TOI-416 and TOI-1143 are totally eclipsing F+M star systems with well-determined secondary masses, radii, and temperatures. TOI-416 is a circular system with an F6 primary and a secondary with a mass of M₂ = 0.131(8) M_⊙. TOI-1143 consists of an F6 primary with an M₂ = 0.142(3) M_⊙ secondary on an eccentric orbit with a third companion. With respect to the other systems, TOI-1153 shows ellipsoidal variations, TOI-1615 contains a pulsating primary, and TOI-1788 has a spotted primary, while all have moderate mass ratios of 0.2–0.4. However, these systems are in a grazing configuration, which limits their full description. The parameters of TOI-416B and TOI-1143B are suitable for the calibration of the radius-mass relation for dwarf stars.