Spatial Distribution and Kinematics of OB Stars

Abstract

The sample of 37 485 suspected OB stars selected by Gontcharov (2008) from the Tycho-2 catalogue has been cleaned of the stars that are not of spectral types OV--A0V. For this purpose, the apparent magnitude $V_T$ from Tycho-2, the absolute magnitude $M_{V_T}$ calibrated as a function of the dereddened color index $(B_T-V_T{)}_0$, the interstellar extinction $A_{V_T}$ calculated from the 3D analytical model by Gontcharov (2009) as a function of the Galactic coordinates, and the photometric distance $r_{ph}$ calculated as a function of $V_T$, $M_{V_T}$, and $A_{V_T}$ have been reconciled in an iterative process. The 20 514 stars that passed the iterations have $(B_T-V_T{)}_0<0$ and $M_{V_T}>-5$ and are considered as a sample of OV--A0V stars complete within 350 pc of the Sun. Based on the theoretical relation between the dereddened color and age of the stars, the derived sample has been divided into three subsamples: $(B_T-V_T{)}_0<-0.2^m$, $-0.2^m<(B_T-V_T{)}_0<-0.1^m$, and $-0.1^m<(B_T-V_T{)}_0<0^m$, younger than 100, $100-200$, and $200-400$ Myr, respectively. The spatial distribution of all 20 514 stars and the kinematics analyzed for more than 1500 stars with radial velocities from the PCRV and RAVE catalogues are different for the subsamples, showing smooth rotations, shears, and deformations of the layer of gas producing stars with the formation of the Gould Belt, the Great Tunnel, the Local Bubble, and other structures within the last 200 Myr. The detected temporal variations of the velocity dispersions, solar motion components, Ogorodnikov--Milne model parameters, and Oort constants are significant, agree with the results of other authors, and show that it is meaningless to calculate the kinematic parameters for samples of stars with uncertain ages or with a wide range of ages.

7 figures, 1 table

References in corpus (9)

• The Radial Velocity Experiment (RAVE): first data release
• 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
• Origin and evolution of moving groups I. Characterization in the observational kinematic-age-metallicity space
• Two-Photon 2s<->1s Transitions during Recombination of Hydrogen in the Universe
• OB Stars in the Solar Neighborhood II: Kinematics
• 3D Interstellar Extinction Map within the Nearest Kiloparsec
• Red Giant Clump in the Tycho-2 Catalogue
• Kinematics of the Gould Belt Based on Open Clusters
• The Red Giant Branch in the Tycho-2 Catalogue

Cited by in corpus (13)

• 3D Stellar Reddening Map from 2MASS Photometry: An Improved Version
• Galactic runaway O and Be stars found using Gaia DR3
• Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars
• Interstellar Extinction
• Substructure, supernovae, and a time-resolved star formation history for Upper Scorpius
• Constraining the initial conditions of NGC 2264 using ejected stars found in Gaia DR2
• {\it Gaia} DR2 giants in the Galactic dust -- I. Reddening across the whole dust layer and some properties of the giant clump
• Kinematics of OB Stars with Data from the LAMOST and Gaia Catalogues
• New Interstellar Extinction Maps Based on Gaia and Other Sky Surveys
• Galaxy Rotation Parameters from OB2 Stars with Proper Motions and Parallaxes from the Gaia EDR3 Catalog
• An unusually large gaseous transit in a debris disc
• On the Properties of the Galactic Dust Layer within 700 pc of the Sun
• A Three-Dimensional Analytical Model of the Interstellar Extinction within the Nearest Kiloparsec