A method to estimate stellar ages from kinematical data

Abstract

We present a method to build a probability density function (pdf) for the age of a star based on its peculiar velocities $U$, $V$ and $W$ and its orbital eccentricity. The sample used in this work comes from the Geneva-Copenhagen Survey (GCS) which contains both the spatial velocities, orbital eccentricities and isochronal ages for about $14000$ stars. Using the GCS stars, we fitted the parameters that describe the relations between the distributions of kinematical properties and age. This parametrization allows us to obtain an age probability from the kinematical data. From this age pdf, we estimate an individual average age for the star using the most likely age and the expected age. We have obtained the stellar age pdf for the age of $9102$ stars from the GCS and have shown that the distribution of individual ages derived from our method is in good agreement with the distribution of isochronal ages. We also observe a decline in the mean metallicity with our ages for stars younger than 7 Gyr, similar to the one observed for isochronal ages. This method can be useful for the estimation of rough stellar ages for those stars that fall in areas of the HR diagram where isochrones are tightly crowded. As an example of this method, we estimate the age of Trappist-1, which is a M8V star, obtaining the age of $t(UVW)=12.50(+0.29-6.23)$ Gyr.

14 pages, 12 Figures

References in corpus (24)

• The Gaia mission
• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• The Radial Velocity Experiment (RAVE): first data release
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• Stellar magnetism: empirical trends with age and rotation
• Scaled solar tracks and isochrones in a large region of the Z-Y plane I. From the ZAMS to the TP-AGB end for 0.15 - 2.5 Mo stars
• The Geneva-Copenhagen Survey of the Solar neighbourhood II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk
• Standing on the shoulders of Dwarfs: the Kepler asteroseismic LEGACY sample II - radii, masses, and ages
• A precise asteroseismic age and radius for the evolved Sun-like star KIC 11026764
• Asteroseismology and Interferometry
• On the Age of the TRAPPIST-1 System
• Re-visiting the relations: Galactic thin disc age-velocity dispersion relation
• Dissecting simulated disc galaxies II: the age-velocity relation
• The Hyades stream: evaporated cluster or intrusion from the inner disk?
• On the age heterogeneity of the Pleiades, Hyades and Sirius moving groups
• A comparison of gyrochronological and isochronal age estimates for transiting exoplanet host stars
• A clear age-velocity dispersion correlation in Andromeda's stellar disk
• Metal enrichment processes
• Accurate age determinations of several nearby open clusters containing magnetic Ap stars
• The effect of starspots on the ages of low-mass stars determined from the lithium depletion boundary
• Kinematic structures of the Solar neighbourhood revealed by Gaia DR1/TGAS and RAVE
• The Contribution of Spiral Arms to the Thick Disk along the Hubble Sequence
• The local standard of rest from data on young objects with account for the Galactic spiral density wave