A 0.24+0.18 M-circle dot double-lined eclipsing binary from the HATSouth survey

作者：Zhou G^*; Bayliss D; Hartman J D; Rabus M; Bakos G A; Jordan A; Brahm R; Penev K; Csubry Z; Mancini L; Espinoza N; de Val Borro M; Bhatti W; Ciceri S; Henning T; Schmidt B; Murphy S J; Butler R P; Arriagada P; Shectman S; Crane J; Thompson I; Suc V; Noyes R W

来源：Monthly Notices of the Royal Astronomical Society, 2015, 451(3): 2263-2277.

DOI：10.1093/mnras/stv1070

• binaries: eclipsing
• stars: individual: HATS551-027

We report the discovery and characterization of a new M-dwarf binary, with component masses and radii of M-1 = 0.244(-0.003)(+0.003) M-circle dot, R-1 = 0.261(-0.009)(+0.006) R-circle dot, M-2 = 0.179(-0.001)(+0.002) M-circle dot, R-2 = 0.218(-0.011)(+0.007) R-circle dot, and orbital period of similar to 4.1 d. The M-dwarf binary HATS551-027 (LP 837-20) was identified as an eclipsing binary by the HATSouth survey, and characterized by a series of high-precision photometric observations of the eclipse events, and spectroscopic determinations of the atmospheric parameters and radial velocity orbits. HATS551-027 is one of few systems with both stellar components lying in the fully convective regime of very low mass stars, and can serve as a test for stellar interior models. The radius of HATS551-027A is consistent with models to 1 sigma, whilst HATS551-027B is inflated by 9 per cent at 2s significance. We measure the effective temperatures for the two stellar components to be T-eff,T- (1) = 3190 +/- 100 K and T-eff, (2) = 2990 +/- 110 K; both are slightly cooler than theoretical models predict, but consistent with other M-dwarfs of similar masses that have previously been studied. We also measure significant Ha emission from both components of the binary system, and discuss this in the context of the correlation between stellar activity and the discrepancies between the observed and model temperatures.

• 出版日期2015-8-11