PHOTOMETRY OF TYPE II CEPHEIDS. I. THE LONG-PERIOD STARS

Authors

Edward G. Schmidt, University of Nebraska-LincolnFollow
Dale Johnston, University of Nebraska-LincolnFollow
Shawn Langan, University of Nebraska-LincolnFollow
Kevin M. Lee, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

10-1-2004

Comments

Published in The Astronomical Journal 128, pp. 1748-1760. (October 2004). Copyright 2004 by the University of Chicago Press and the American Astronomical Society. Journal homepage = http://www.journals.uchicago.edu/AJ/
Reproduced by permission of the AAS.

Abstract

We present 1256 new photometric observations of 36 Cepheids with periods longer than 8 days. The majority are likely type II Cepheids, but we have included about a dozen classical Cepheids for comparison purposes, a few stars of uncertain type, and one putative RV Tauri star. We discuss the appearance of the light curves, the Fourier parameters, and the light-curve stability in terms of differentiation between type I and type II Cepheids. Although we encounter the same difficulties as previous investigators in using these parameters for this purpose, we are able to identify some stars of particular interest, including several likely type I Cepheids at large distances from the Galactic plane. Six stars with especially large period changes are identified and discussed.