How to Constrain Your M Dwarf. II. the Mass-Luminosity-Metallicity Relation from 0.075 to 0.70 Solar Masses
Date
2019
Authors
Mann, Andrew W.
Dupuy, Trent
Kraus, A L
Gaidos, Eric
Ansdell, Megan
Ireland, Michael
Rizzuto, Aaron C.
Hung, Chao-Ling
Dittmann, Jason
Factor, Samuel
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Volume Title
Publisher
IOP Publishing
Abstract
The mass–luminosity relation for late-type stars has long been a critical tool for estimating stellar masses.
However, there is growing need for both a higher-precision relation and a better understanding of systematic
effects (e.g., metallicity). Here we present an empirical relationship between MKS and M* spanning
0.075 Me < M* < 0.70 Me. The relation is derived from 62 nearby binaries, whose orbits we determine using
a combination of Keck/NIRC2 imaging, archival adaptive optics data, and literature astrometry. From their orbital
parameters, we determine the total mass of each system, with a precision better than 1% in the best cases. We use
these total masses, in combination with resolved KS magnitudes and system parallaxes, to calibrate the MKS–M* relation. The resulting posteriors can be used to determine masses of single stars with a precision of 2%–3%, which
we confirm by testing the relation on stars with individual dynamical masses from the literature. The precision is
limited by scatter around the best-fit relation beyond measured M* uncertainties, perhaps driven by intrinsic
variation in the MKS–M* relation or underestimated uncertainties in the input parallaxes. We find that the effect of
[Fe/H] on the MKS–M* relation is likely negligible for metallicities in the solar neighborhood (0.0% ± 2.2%
change in mass per dex change in [Fe/H]). This weak effect is consistent with predictions from the Dartmouth
Stellar Evolution Database, but inconsistent with those from MESA Isochrones and Stellar Tracks (at 5σ). A
sample of binaries with a wider range of abundances will be required to discern the importance of metallicity in
extreme populations (e.g., in the Galactic halo or thick disk).
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Keywords
binaries: visual, stars: late-type, stars: low-mass, stars: luminosity function, mass function Supporting material: machine-readable tables
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Source
The Astrophysical Journal
Type
Journal article
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Open Access
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