paper

Galactic Kinematics from OB3 Stars with Distances determined from Interstellar Ca II Lines

arXiv:1106.5849 · doi:10.1134/S0320010811070011

Abstract

Based on data for 102 OB3 stars with known proper motions and radial velocities, we have tested the distances derived by Megier et al. from interstellar Ca II spectral lines. The internal reconciliation of the distance scales using the first derivative of the angular velocity of Galactic rotation Ω'0 and the external reconciliation with Humphreys's distance scale for OB associations refined by Mel'nik and Dambis show that the initial distances should be reduced by \approx 20%. Given this correction, the heliocentric distances of these stars lie within the range 0.6-2.6 kpc. A kinematic analysis of these stars at a fixed Galactocentric distance of the Sun, R0=8 kpc, has allowed the following parameters to be determined:(1) the solar peculiar velocity components (U_o,V_o,W_o)=(8.9,10.3,6.8)\pm(0.6,1.0,0.4) km/s;(2) the Galactic rotation parameters Ω_o=-31.5\pm0.9 km/s/kpc, Ω'_o=+4.49\pm0.12 km/s/kpc^2, Ω"_o=-1.05\pm0.38 km/s/kpc^3, (the corresponding Oort constants are A=17.9\pm0.5 km/s/kpc, B=-13.6\pm1.0 km/s/kpc and the circular rotation velocity of the solar neighborhood is |V_o|=252\pm14 km/s); (3) the spiral density wave parameters, namely: the perturbation amplitudes for the radial and azimuthal velocity components, respectively, f_R = -12.5\pm1.1 km/s and f_θ=2.0\pm1.6 km/s; the pitch angle for the two-armed spiral pattern i=-5.3\pm0.3 degrees, with the wavelength of the spiral density wave at the solar distance being λ=2.3\pm0.2 kpc; the Sun's phase in the spiral wave χ_o=-91\pm4 degrees.

14 pages, 4 figures, 3 tables

References in corpus (8)

Galactic Kinematics from OB3 Stars with Distances determined from Interstellar Ca II Lines · wovepaper