TY - JOUR
T1 - The EBLM Project. V. Physical properties of ten fully convective, very-low-mass stars
AU - von Boetticher, Alexander
AU - Triaud, Amaury H. M. J.
AU - Queloz, Didier
AU - Gill, Sam
AU - Maxted, Pierre F. L.
AU - Almleaky, Yaseen
AU - Anderson, David R.
AU - Bouchy, Francois
AU - Burdanov, Artem
AU - Cameron, Andrew Collier
AU - Delrez, Laetitia
AU - Ducrot, Elsa
AU - Faedi, Francesca
AU - Gillon, Michaël
AU - Chew, Yilen Gómez Maqueo
AU - Hebb, Leslie
AU - Hellier, Coel
AU - Jehin, Emmanuël
AU - Lendl, Monika
AU - Marmier, Maxime
AU - Martin, David V.
AU - McCormac, James
AU - Pepe, Francesco
AU - Pollacco, Don
AU - Ségransan, Damien
AU - Smalley, Barry
AU - Thompson, Samantha
AU - Turner, Oliver
AU - Udry, Stéphane
AU - Grootel, Valérie Van
AU - West, Richard
N1 - The research leading to these results has received fund-ing from the European Research Council under the FP/2007-2013 ERC Grant Agreement n◦336480; the European Union’s Horizon 2020 research and innovation program, grant agreement n◦803193/BEBOP; and from the ARC grant for Concerted Research Actions, financed by the Wallonia-Brussels Federation.
PY - 2019/6/4
Y1 - 2019/6/4
N2 - Measurements of the physical properties of stars at the lower end of the main sequence are scarce. In this context we report masses, radii and surface gravities of ten very-low-mass stars in eclipsing binary systems, with orbital periods of the order of several days. The objects probe the stellar mass-radius relation in the fully convective regime, M* ≲ 0.35 M⊙, down to the hydrogen burning mass-limit, MHB ∼ 0.07 M⊙. The stars were detected by the WASP survey for transiting extra-solar planets, as low-mass, eclipsing companions orbiting more massive, F- and G-type host stars. We use eclipse observations of the host stars, performed with the TRAPPIST, Leonhard Euler, SPECULOOS telescopes, and radial velocities of the host stars obtained with the CORALIE spectrograph, to determine physical properties of the low-mass companions. Surface gravities of the low mass companions are derived from the eclipse and orbital parameters of each system. Spectroscopic measurements of the host star effective temperature and metallicity are used to infer the host star mass and age from stellar evolution models for solar-type stars. Masses and radii of the low-mass companions are then derived from the eclipse and orbital parameters of each system. The objects are compared to stellar evolution models for low-mass stars, to test for an effect of the stellar metallicity and orbital period on the radius of low-mass stars in close binary systems. Measurements are found to be in good agreement with stellar evolution models; an systematic inflation of the radii of low-mass stars with respect to model predictions is limited to 1.6 ± 1.2% in the fully convective low-mass regime. The sample of ten objects indicates a scaling of the radius of low-mass stars with the host star metallicity. No correlation between stellar radii and orbital periods of the binary systems is determined. A combined analysis with thirteen comparable objects from the literature is consistent with this result.
AB - Measurements of the physical properties of stars at the lower end of the main sequence are scarce. In this context we report masses, radii and surface gravities of ten very-low-mass stars in eclipsing binary systems, with orbital periods of the order of several days. The objects probe the stellar mass-radius relation in the fully convective regime, M* ≲ 0.35 M⊙, down to the hydrogen burning mass-limit, MHB ∼ 0.07 M⊙. The stars were detected by the WASP survey for transiting extra-solar planets, as low-mass, eclipsing companions orbiting more massive, F- and G-type host stars. We use eclipse observations of the host stars, performed with the TRAPPIST, Leonhard Euler, SPECULOOS telescopes, and radial velocities of the host stars obtained with the CORALIE spectrograph, to determine physical properties of the low-mass companions. Surface gravities of the low mass companions are derived from the eclipse and orbital parameters of each system. Spectroscopic measurements of the host star effective temperature and metallicity are used to infer the host star mass and age from stellar evolution models for solar-type stars. Masses and radii of the low-mass companions are then derived from the eclipse and orbital parameters of each system. The objects are compared to stellar evolution models for low-mass stars, to test for an effect of the stellar metallicity and orbital period on the radius of low-mass stars in close binary systems. Measurements are found to be in good agreement with stellar evolution models; an systematic inflation of the radii of low-mass stars with respect to model predictions is limited to 1.6 ± 1.2% in the fully convective low-mass regime. The sample of ten objects indicates a scaling of the radius of low-mass stars with the host star metallicity. No correlation between stellar radii and orbital periods of the binary systems is determined. A combined analysis with thirteen comparable objects from the literature is consistent with this result.
KW - Stars; low-mass
KW - Binaries: eclipsing
KW - Binaries: spectroscopic
KW - Techniques: photometric
U2 - 10.1051/0004-6361/201834539
DO - 10.1051/0004-6361/201834539
M3 - Article
SN - 0004-6361
VL - 625
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
M1 - A150
ER -