Mass-Radius relation of low-mass stars revisitedwith the VLTI

摘要

We report the measurements of 5 single, low-mass and very low-mass stars angular di-ameter obtained with VINCI (VLT Interferometer Commissioning Instrument) in 2002 and AMBER(Astronomical Multi-BEam Recombiner) since 2007 on the VLTI array. We determined radii withaccuracies of 1 to 5% for low-mass and very low mass stars ranging from M5.5V to K0.5V, thusencompassing a good fraction of the M-R relation for low-mass stars. Those results allow to revisitthe current state of mass-radius relation for those objects from which a good agreement with modelsis shown up to about 0.6-0.7 solar masses. We explore remaining discrepancies in the upper part ofthe mass-radius relation and point out effects that may be due to stellar metallicity.