UNRAVELING TIC-49899799: A NEW DETACHED M-DWARF ECLIPSING BINARY SYSTEM FROM THE TRANSITING EXOPLANET SURVEY SATELLITE (TESS)

Abstract

We report the discovery of a new detached M-dwarf eclipsing binary System: TIC – 49899799. This single-lined spectroscopic binary (SB1) system was first observed by TESS through the 30-minute cadence Full-Frame Images in 2018. This system has an orbital period of P = 7.0114+3.7×10−7 days as confirmed from the folded and phased light curve. Spectroscopic radial velocity follow-up observations from CHIRON at the SMARTS 1.5m telescope suggest that the system is in a nearly circular orbit with eccentricity close to zero and a mass-ratio of M2/M1 = 0.0867+0.0022, with component masses of M1 = 1.6501+0.0986 M0 and M2 = 0.1666+0.0031 M0. From the light curve and spectral energy −0.1317 −0.003 distribution (SED) fit, we also calculate the radii of the components to be R1 = 1.9074+0.0338 R0 and R2 = 0.1424+0.0057 R0. Interestingly, the measured radius for secondary component is about the same as predicted by stellar models, which contradicts an incidence of radius inflation in such low mass detached eclipsing binary systems. This illustrates the importance of continuing characterization observations of these types of low-mass stars: to better understand how the observed, rather than the theoretical, stellar properties of low-mass M-dwarfs can affect potentially habitable exoplanets in orbit about these stars containing Earth-like exoplanets.