Orbital Parameters and Binary Properties of 37 FGK stars in the Cores of Open Clusters NGC 2516 and NGC 2422
arXiv:2110.01815 · doi:10.3847/1538-3881/ac2ccd
Abstract
We present orbits for 24 binaries in the field of open cluster NGC 2516 (~150 Myr) and 13 binaries in the field of open cluster NGC 2422 (~130 Myr) using results from a multi-year radial velocity survey of the cluster cores. Six of these systems are double-lined spectroscopic binaries (SB2s). We fit these RV variable systems with orvara, a MCMC-based fitting program that models Keplerian orbits. We use precise stellar parallaxes and proper motions from Gaia EDR3 to determine cluster membership. We impose a barycentric radial velocity prior on all cluster members; this significantly improves our orbital constraints. Two of our systems have periods between 5 and 15 days, the critical window in which tides efficiently damp orbital eccentricity. These binaries should be included in future analyses of circularization across similarly-aged clusters. We also find a relatively flat distribution of binary mass ratios, consistent with previous work. With the inclusion of TESS lightcurves for all available targets, we identity target 378-036252 as a new eclipsing binary. We also identify a field star whose secondary has a mass in the brown dwarf range, as well as two cluster members whose RVs suggest the presence of an additional companion. Our orbital fits will help constrain the binary fraction and binary properties across stellar age and across stellar environment.
38 pages, 47 figures (incl. 37 Appendix figures), 4 tables. AJ accepted
References in corpus (13)
- The Gaia mission
- The Transiting Exoplanet Survey Satellite
- Gaia Early Data Release 3: The astrometric solution
- Efficient fitting of multiplanet Keplerian models to radial velocity and astrometry data
- Observational Evidence for Tidal Interaction in Close Binary Systems
- Close companions around young stars
- orvara: An Efficient Code to Fit Orbits using Radial Velocity, Absolute, and/or Relative Astrometry
- A high binary fraction for the most massive close-in giant planets and brown dwarf desert members
- Wide binaries are rare in open clusters
- Stellar Radial Velocities in the Old Open Cluster M67 (NGC 2682). II. The Spectroscopic Binary Population
- The rotation period distribution of the rich Pleiades-age Southern open cluster NGC 2516. Existence of a representative zero-age main sequence distribution
- Twins Among the Low Mass Spectroscopic Binaries
- Different Dynamical Ages for the Two Young and Coeval LMC Star Clusters NGC 1805 and NGC 1818 Imprinted on Their Binary Populations