SCYON Abstract

Received on May 22 2001

Periodic Pattern in the Field of Residual Velocities of OB-Associations

AuthorsA. M. Mel'nik, A. K. Dambis, and A. S. Rastorguev
AffiliationSternberg Astronomical Institute, Universitetskii pr. 13, Moscow, 119899 Russia
Accepted byAstronomy Letters


An analysis of the field of residual velocities of OB-associations located within 3 kpc from the Sun revealed periodic variations in the radial components of residual velocities along the galactic radius-vector with a typical scale length of lambda=2.0 ± 0.2 kpc and a mean amplitude of fR = 7 ± km/s. The fact that radial residual velocities of almost all OB-associations in rich stellar-gas complexes are directed toward the Galactic center indicates that the solar neighborhood considered is located inside the corotation radius. The field of azimuthal velocities exhibits a conspicuous periodic pattern with a mean amplitude of ftheta = 6 ± 2 km/s in the 0 < l < 180° region and no periodic variations in the 180 < l < 360° region. The locations of the Cygnus and Perseus arms as inferred from an analysis of the fields of radial and azimuthal velocities agree with each other. The periodic patterns of the fields of residual velocities of Cepheids and OB-associations are found to have many common features.