Daily Archives: July 21, 2006

The period-luminosity relation for type II Cepheids in GCs

New paper:

Matsunaga, Noriyuki et al.

The period-luminosity relation for type II Cepheids in globular clusters

We report the result of our near-infrared observations (JHKs) for type II Cepheids (including possible RV Tau stars) in galactic globular clusters. We detected variations of 46 variables in 26 clusters (10 new discoveries in seven clusters) and present their light curves. Their periods range from 1.2 d to over 80 d. They show a well-defined period-luminosity relation at each wavelength. Two type II Cepheids in NGC 6441 also obey the relation if we assume the horizontal branch stars in NGC 6441 are as bright as those in metal-poor globular clusters in spite of the high metallicity of the cluster. This result supports the high luminosity which has been suggested for the RR Lyr variables in this cluster (…)

Publication: Monthly Notices of the Royal Astronomical Society, Online Early