http://arxiv.org/abs/2109.00836
We present the discovery and characterisation of an eclipsing binary identified by the Next Generation Transit Survey in the $\sim$115 Myr old Blanco 1 open cluster. NGTS J0002-29 comprises three M dwarfs: a short-period binary and a companion in a wider orbit. This system is the first well-characterised, low-mass eclipsing binary in Blanco 1. With a low mass ratio, a tertiary companion and binary components that straddle the fully convective boundary, it is an important benchmark system, and one of only two well-characterised, low-mass eclipsing binaries at this age. We simultaneously model light curves from NGTS, TESS, SPECULOOS and SAAO, radial velocities from VLT/UVES and Keck/HIRES, and the system’s spectral energy distribution. We find that the binary components travel on circular orbits around their common centre of mass in $P_{\rm orb} = 1.09800524 \pm 0.00000038$ days, and have masses $M_{\rm pri}=0.3978\pm 0.0033$ M${\odot}$ and $M{\rm sec}=0.2245\pm 0.0018$ M${\odot}$, radii $R{\rm pri}=0.4037\pm 0.0048$ R${\odot}$ and $R{\rm sec}=0.2759\pm 0.0055$ R${\odot}$, and effective temperatures $T{\rm pri}=3372\,^{+44}{-37}$ K and $T{\rm sec}=3231\,^{+38}_{-31}$ K. We compare these properties to the predictions of seven stellar evolution models, which typically imply an inflated primary. The system joins a list of 19 well-characterised, low-mass, sub-Gyr, stellar-mass eclipsing binaries, which constitute some of the strongest observational tests of stellar evolution theory at low masses and young ages.
G. Smith, E. Gillen, D. Queloz, et. al.
Fri, 3 Sep 21
23/52
Comments: 21 pages, 9 figures. Accepted for publication in MNRAS
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