The Luminosity and Mass Functions of Low-mass Stars in the Galactic Disk. II. The Field
Abstract
We report on new measurements of the luminosity function (LF) and mass function (MF) of field low-mass dwarfs derived from Sloan Digital Sky Survey Data Release 6 photometry. The analysis incorporates ~15 million low-mass stars (0.1 {\cal M}_\odot {\cal M} < 0.8\,{\cal M}_\odot), spread over 8400 deg2. Stellar distances are estimated using new photometric parallax relations, constructed from ugriz photometry of nearby low-mass stars with trigonometric parallaxes. We use a technique that simultaneously measures Galactic structure and the stellar LF from 7 < Mr < 16. We compare the LF to previous studies and convert to an MF using the mass-luminosity relations of Delfosse et al. The system MF, measured over -1.0< log {\cal M} / {\cal M}_\odot <-0.1, is well described by a lognormal distribution with {\cal M}_{\circ } = 0.25 {\cal M}_\odot. We stress that our results should not be extrapolated to other mass regimes. Our work generally agrees with prior low-mass stellar MFs and places strong constraints on future theoretical star formation studies.
- Publication:
-
The Astronomical Journal
- Pub Date:
- June 2010
- DOI:
- 10.1088/0004-6256/139/6/2679
- arXiv:
- arXiv:1004.4002
- Bibcode:
- 2010AJ....139.2679B
- Keywords:
-
- brown dwarfs;
- Galaxy: stellar content;
- Galaxy: structure;
- stars: fundamental parameters;
- stars: late-type;
- stars: low-mass;
- stars: luminosity function;
- mass function;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 23 pages, 27 figures, emulateapj format. Accepted for publication in AJ