Bayesian Ages for Early-type Stars from Isochrones Including Rotation, and a Possible Old Age for the Hyades
Abstract
We combine recently computed models of stellar evolution using a new treatment of rotation with a Bayesian statistical framework to constrain the ages and other properties of early-type stars. We find good agreement for early-type stars and clusters with known young ages, including β Pictoris, the Pleiades, and the Ursa Majoris moving group. However, we derive a substantially older age for the Hyades open cluster (750 ± 100 Myr compared to 625 ± 50 Myr). This older age results from both the increase in main-sequence lifetime with stellar rotation and from the fact that rotating models near the main-sequence turnoff are more luminous, overlapping with slightly more massive (and shorter-lived) nonrotating ones. Our method uses a large grid of nonrotating models to interpolate between a much sparser rotating grid, and also includes a detailed calculation of synthetic magnitudes as a function of orientation. We provide a web interface at http://www.bayesianstellarparameters.info, where the results of our analysis may be downloaded for individual early-type (B-V≲ 0.25) Hipparcos stars. The web interface accepts user-supplied parameters for a Gaussian metallicity prior and returns posterior probability distributions on mass, age, and orientation.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 2015
- DOI:
- 10.1088/0004-637X/807/1/58
- arXiv:
- arXiv:1501.04404
- Bibcode:
- 2015ApJ...807...58B
- Keywords:
-
- Hertzsprung–Russell and C–M diagrams;
- methods: statistical;
- stars: early-type;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 11 pages, 6 figures, ApJ accepted. Error fixed: ages ->