Milky Way rotation and the distance to the Galactic center from Cepheid variables

  • J. A. R. Caldwell
  • I. M. Coulson
I. Fundamental Parameters: Scale, Rotation and Mass
Part of the Lecture Notes in Physics book series (LNP, volume 306)


The existing data on Milky Way Cepheids are fitted with an axisymmetric Galactic rotation model. A new “standard candle” mo is determined: the unreddened apparent magnitude of a hypothetical Cepheid with standard period, color, and metallicity at a distance of 1 Ro. It then follows that Ro = 7.8 ± 0.7 kpc from the cluster Cepheid zero point. Further important results are that 2AR0 = 228 ± 19 km s−1, and that the observed Cepheid mean velocities average 3.1 ± 0.9 km s−1 too negative compared with the center-of-mass velocities.


Radial Velocity Rotation Curve Galactic Center Galactic Plane Standard Candle 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Caldwell, J.A.R., and Coulson, I.M. (1987). Astron.J. 93,1090.Google Scholar
  2. Kraft, R.P., and Schmidt, M. (1963). Astrophys.J. 137,249.Google Scholar

Copyright information

© Springer-Verlag 1988

Authors and Affiliations

  • J. A. R. Caldwell
    • 1
  • I. M. Coulson
    • 2
  1. 1.Mount Wilson and Las Campanas ObservatoriesPasadenaUSA
  2. 2.South African Astronomical ObservatorySouth Africa

Personalised recommendations