Kinematics of B-F Stars as a Function of Their Dereddened Color from Gaia and PCRV Data

Abstract

Parallaxes with an accuracy better than 10% and proper motions from the Gaia DR1 TGAS catalogue, radial velocities from the PCRV, Tycho-2 photometry, PARSEC, MIST, YaPSI, BaSTI isochrones, and the most accurate reddening and extinction estimates have been used to analyze the kinematics of 9543 thin-disk B-F stars as a function of their dereddened color. These stars are located on the Hertzsprung-Russell diagram relative to the isochrones with a high accuracy. This has allowed me to conclude that the reddening and extinction were significantly underestimated in some kinematic studies of other authors. The median accuracy of the velocity components U, V, W in this study is 1.7 km/s, although outside the range $-0.1<(B_T-V_T{)}_0<0.5$ the kinematic characteristics are noticeably biased due to the incompleteness of the sample. We have confirmed the variations in the mean velocity of stars relative to the Sun and the stellar velocity dispersion as a function of their dereddened color known from the Hipparcos data. Given the age estimates for the stars under consideration from the TRILEGAL model and the Geneva-Copenhagen survey, these variations may be considered as variations as a function of the age. A comparison of our results with the results of other studies of the stellar kinematics near the Sun has shown that selection and reddening underestimation explain almost completely the discrepancies between the results. The dispersions and mean velocities from the results of reliable studies fit into a $\pm 2$ km/s corridor, while the ratios ${\sigma }_V/{\sigma }_U$ and ${\sigma }_W/{\sigma }_U$ fit into $\pm 0.05$. Based on all reliable studies in the range $-0.1<(B_T-V_T{)}_0<0.5$, i.e., for an age from 0.23 to 2.4 Gyr, we have found that the stellar velocity dispersions in km/s are proportional to the age in Gyr raised to the power ${\beta }_U=0.33$, ${\beta }_V=0.285$, and ${\beta }_W=0.37$.

8 figures, published in Astronomy Letters, 2018, 44, 248-264

References in corpus (24)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• The Radial Velocity Experiment (RAVE): Fifth Data Release
• 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
• Pulkovo Compilation of Radial Velocities for 35495 Hipparcos Stars in a Common System
• The Tycho-Gaia astrometric solution. How to get 2.5 million parallaxes with less than one year of Gaia data
• Estimating distances from parallaxes. III. Distances of two million stars in the Gaia DR1 catalogue
• Kinematic modelling of the Milky Way using the RAVE and GCS stellar surveys
• The Yale-Potsdam Stellar Isochrones (YaPSI)
• Age velocity dispersion relations and heating histories in disc galaxies
• Modeling Thermal Dust Emission with Two Components: Application to the Planck HFI Maps
• Revisiting two local constraints of the Galactic chemical evolution
• Calculation of the Local Standard of Rest from 20,574 Local Stars in the New Hipparcos Reduction with Known Radial Velocities
• 3D Stellar Reddening Map from 2MASS Photometry: An Improved Version
• Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars
• Variations of the Interstellar Extinction Law within the Nearest Kiloparsec
• 3D Interstellar Extinction Map within the Nearest Kiloparsec
• On the discrepancy between asteroseismic and Gaia DR1 TGAS parallaxes
• The Red Giant Branch in the Tycho-2 Catalogue
• Systematic Error of the Gaia DR1 TGAS Parallaxes from Data for the Red Giant Clump
• Using the reduced proper motions of Tycho-2 stars with B-V from 0.75 to 1.25: Monte Carlo simulations
• Maximum likelihood estimation of local stellar kinematics
• Comparison of the Pulkovo Compilation of Radial Velocities with the RAVE DR1 Catalogue