Colors and Kinematics of L Dwarfs from the Sloan Digital Sky Survey
Abstract
We present a sample of 484 L dwarfs, 210 of which are newly discovered from the Sloan Digital Sky Survey (SDSS) Data Release 7 spectroscopic database. We combine this sample with known L dwarfs to investigate their izJHKS colors. Our spectroscopically selected sample has ~0.1 mag bluer median J - KS color at a given spectral type (for L0-L4) than previously known L dwarfs, which reflects a bias toward redder L dwarfs in past selection criteria. We present photometric distance relations based on i - z and i - J colors and derive distances to our L dwarf sample. We combine the distances with SDSS/2MASS proper motions in order to examine the tangential velocities. For the majority of our spectroscopic sample, we measured radial velocities and present three-dimensional kinematics. We also provide Hα detections for the fraction of our sample with sufficient quality spectra. Comparison of the velocities of our L dwarf sample to a kinematic model shows evidence for both cold and hot dynamical populations, consistent with young and old disk components. The dispersions of these components are similar to those found for M dwarfs. We also show that J - KS color is correlated with velocity dispersion, confirming a relationship between J - KS color and age.
- Publication:
-
The Astronomical Journal
- Pub Date:
- May 2010
- DOI:
- 10.1088/0004-6256/139/5/1808
- arXiv:
- arXiv:1001.3402
- Bibcode:
- 2010AJ....139.1808S
- Keywords:
-
- brown dwarfs;
- solar neighborhood;
- stars: kinematics and dynamics;
- stars: low-mass;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 58 pages, 11 figures, 8 tables, accepted for publication in the Astronomical Journal