The Chromospheric Activity and Ages of M Dwarf Stars in Wide Binary Systems
Abstract
We investigate the relationship between age and chromospheric activity for 139 M dwarf stars in wide binary systems with white dwarf companions. The age of each system is determined from the cooling age of its white dwarf component. The current limit for activity-age relations found for M dwarfs in open clusters is 4 Gyr. Our unique approach to finding ages for M stars allows for the exploration of this relationship at ages older than 4 Gyr. The general trend of stars remaining active for a longer time at a later spectral type is confirmed. However, our larger sample and greater age range reveal additional complexity in assigning age based on activity alone. We find that M dwarfs in wide binaries older than 4 Gyr depart from the loglinear relation for clusters and are found to have activity at magnitudes, colors, and masses that are brighter, bluer, and more massive than predicted by the cluster relation. In addition to our activity-age results, we present the measured radial velocities and complete space motions for 161 white dwarf stars in wide binaries.
Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium; the Cerro Tololo Inter-American Observatory 4.0 m telescope, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under a cooperative agreement with the National Science Foundation (NSF) as part of the National Optical Astronomy Observatory (NOAO), which also operates Kitt Peak National Observatory in Tucson, Arizona; and the SARA Observatory 0.9 m telescope at Kitt Peak, which is owned and operated by the Southeastern Association for Research in Astronomy (http://www.saraobservatory.org).- Publication:
-
The Astronomical Journal
- Pub Date:
- May 2005
- DOI:
- 10.1086/429593
- arXiv:
- arXiv:astro-ph/0502305
- Bibcode:
- 2005AJ....129.2428S
- Keywords:
-
- Stars: Binaries: Visual;
- Galaxy: Structure;
- Stars: Activity;
- Stars: Low-Mass;
- Brown Dwarfs;
- Techniques: Spectroscopic;
- Stars: White Dwarfs;
- Astrophysics
- E-Print:
- 22 pages including 9 figures and 5 tables. Accepted for publication in The Astronomical Journal