The Solar Neighborhood. Xxxvii. The Mass–luminosity Relation for Main-Sequence M Dwarfs*

Abstract

We present a Mass-Luminosity Relation (MLR) for red dwarfs spanning a range of masses from 0.62 M to the end of the stellar main sequence at 0.08 M . The relation is based on 47 stars for which dynamical masses have been determined, primarily using astrometric data from Fine Guidance Sensors (FGS) 3 and 1r, white-light interferometers on the Hubble Space Telescope (HST), and radial velocity data from McDonald Observatory. For our HST/FGS sample of 15 binaries, component mass errors range from 0.4% to 4.0% with a median error of 1.8%. With these and masses from other sources, we construct a V -band MLR for the lower main sequence with 47 stars, and a K-band MLR with 45 stars with fit residuals half of those of the V -band.We use GJ 831 AB as an example, obtaining an absolute trigonometric parallax, π abs = 125.3 ± 0.3 milliseconds of arc, with orbital elements yielding M A = 0.270 ± 0.004M and M B = 0.145 ± 0.002M . The mass precision rivals that derived for eclipsing binaries.

THE SOLAR NEIGHBORHOOD. XXXVIII. RESULTS FROM THE CTIO/SMARTS 0.9 m: TRIGONOMETRIC PARALLAXES FOR 151 NEARBY M DWARF SYSTEMS

“…While previous work has reported the census of the 5 pc sample (Henry 2015, pp. 286-290) and 10 pc sample (Henry et al 2006 andT. J. Henry 2016, in preparation), we are Note.…”

“…We define M dwarfs to have 3.7  -V K ( ) 9.5 and 8.8  M V  20.0, corresponding to objects with masses 0.64-0.075  M (Benedict et al 2016). For the most massive M dwarfs, these color and absolute magnitude limits were determined at the K/M dwarf boundary by creating observational HR diagrams from the RECONS 25 Parsec Database (see Section 7), where spectral types from RECONS' work, Gray et al (2003), Reid et al (1995), and Hawley et al (1996) were used to separate the K and M dwarfs.…”

New Low-mass Eclipsing Binary Systems in Praesepe Discovered by K2

“…We estimated primary masses from absolute K-band magnitudes using the semi-empirical relation of Mann et al (2015;their Equation (10)) and the empirical relation of Benedict et al (2016;their Equation (11)). For this, we converted apparent to absolute magnitudes assuming a cluster distance of  182.8 14 pc (Gaia Collaboration et al 2017) and assumed a reddening along the line of sight of…”

The discrepancy between dynamical and theoretical mass in the triplet-system 2MASS J10364483+1521394

“…We reason that A should be of same order in terms of mass as the combined B+C, even slightly more so as it is brighter than the combined brightness of B+C, yet we do not expect the mass of A alone to exceed 0.6 M based on their relative brightness. In order to give a mass estimate purely based on photometry we adopt the mass-luminosity relation of Benedict et al (2016) as…”