New Evolutionary Tracks for Very Low Mass Stars
Abstract
We present new evolutionary calculations for low-mass and very low mass M dwarfs, for a metallicity range -2 ≤ [M/H] ≤ 0, down to the hydrogen-burning minimum mass (0.07 < M/Msun < 0.6). We use the most recent atmosphere models calculated by Allard & Hauschildt (1995), based on synthetic spectra at finite metallicity, and gray atmosphere models based on Alexander & Ferguson (1994) Rosseland opacities.
Comparisons are made with observational results down to the bottom of the main sequence, for different metallicities, in magnitude-color and color-color diagrams. We find excellent agreement between theory and observations over the whole characteristic temperature/luminosity range. This enables us to determine the mass of the faintest objects observed, which is found to be mlim ≈ 0.085 Msun for [M/H] = 0 and -0.5, and mlim = 0.09 Msun for [M/H] = -1.5, for an age of 10 Gyr. We also examine the effect of the age, the metallicity, and the outer boundary conditions on the evolution.- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1995
- DOI:
- 10.1086/187924
- Bibcode:
- 1995ApJ...446L..35B
- Keywords:
-
- STARS: LOW-MASS;
- BROWN DWARFS;
- STARS: EVOLUTION;
- STARS: LATE-TYPE