Space Velocities of Nearby Classical Cepheids

Details Space Velocities of Nearby Classical Cepheids Space Velocities of Nearby Classical Cepheids

Apr 1974

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1974a%26as...15....1w&link_type=abstract

Astronomy and Astrophysics, Suppl. Ser. 15, 1-33

Astronomy and Astrophysics

Astrophysics

34

Scientific paper

The space velocities of the 45 classical cepheids with distances r <= 1 kpc are derived and discussed. Only 12 nearby cepheids have reliable individual space velocities (mean error <= +- 8 km/s). The velocity distribution of the nearby cepheids reveals no obvious systematic behaviour of the peculiar velocities. The mean motion of the nearby cepheids with respect to the sun is found to be = -11 km/s, = -12 km/s, = -10 km/s, with a mean error of +- 2 km/s. Hence the average motion of the nearby cepheids in the galactic plane does not differ significantly from the commonly adopted circular velocity of galactic rotation. The velocity dispersion in U, V and W is +- 8 km/s, +- 7 km/s and +-5 km/s, respectively. The kinematical data of the nearby cepheids confirm the distance scale of classical cepheids based on cluster members, since the method of secular parallaxes yields only an insignificant decrease of the distances by -10% +- 20% (m.e.).