COLORS AND KINEMATICS OF L DWARFS FROM THE SLOAN DIGITAL SKY SURVEY

• Main Authors: Schmidt, Sarah J. (Author), Hawley, Suzanne L. (Author), Pineda, J. Sebastian (Contributor), West, A. A. (Author)
• Other Authors: MIT Kavli Institute for Astrophysics and Space Research (Contributor), West, Andrew A. (Contributor)
• Format: Article
• Language: English
• Published: IOP Publishing, 2015-01-22T18:50:24Z.
• Subjects: Article
• Online Access: Get fulltext

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 izJHK[subscript S] colors. Our spectroscopically selected sample has ~0.1 mag bluer median J - K[subscript S] 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 - K[subscript S] color is correlated with velocity dispersion, confirming a relationship between J - K[subscript S] color and age.
National Science Foundation (U.S.) (Grant AST 06-07644)