The 3D Galactocentric velocities of Kepler stars: marginalizing over missing RVs
arXiv:2205.08901 · doi:10.3847/1538-3881/ac6fea
Abstract
Precise Gaia measurements of positions, parallaxes, and proper motions provide an opportunity to calculate 3D positions and 2D velocities (i.e. 5D phase-space) of Milky Way stars. Where available, spectroscopic radial velocity (RV) measurements provide full 6D phase-space information, however there are now and will remain many stars without RV measurements. Without an RV it is not possible to directly calculate 3D stellar velocities, however one can infer 3D stellar velocities by marginalizing over the missing RV dimension. In this paper, we infer the 3D velocities of stars in the Kepler field in Cartesian Galactocentric coordinates (vx, vy, vz). We directly calculate velocities for around a quarter of all Kepler targets, using RV measurements available from the Gaia, LAMOST and APOGEE spectroscopic surveys. Using the velocity distributions of these stars as our prior, we infer velocities for the remaining three-quarters of the sample by marginalizing over the RV dimension. The median uncertainties on our inferred vx, vy, and vz velocities are around 4, 18, and 4 km/s, respectively. We provide 3D velocities for a total of 148,590 stars in the Kepler field. These 3D velocities could enable kinematic age-dating, Milky Way stellar population studies, and other scientific studies using the benchmark sample of well-studied Kepler stars. Although the methodology used here is broadly applicable to targets across the sky, our prior is specifically constructed from and for the Kepler field. Care should be taken to use a suitable prior when extending this method to other parts of the Galaxy.
Accepted for publication in AAS Journals
References in corpus (15)
- Array Programming with NumPy
- The Gaia mission
- Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
- Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
- New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
- 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
- Calibrating Gyrochronology using Kepler Asteroseismic targets
- The age-velocity dispersion relation of the Galactic discs from LAMOST-Gaia data
- Exploring the age dependent properties of M and L dwarfs using Gaia and SDSS
- Chemical Evolution in the Milky Way: Rotation-based ages for APOGEE-Kepler cool dwarf stars
- Exploring the evolution of stellar rotation using Galactic kinematics
- Gyro-Kinematic Ages for around 30,000 Kepler Stars
- The stellar velocity distribution function in the Milky Way galaxy
- Machine Learning the 6th Dimension: Stellar Radial Velocities from 5D Phase-Space Correlations
- Astrometric radial velocities for nearby stars