Photometry from the HIPPARCOS Catalogue: Constant MCP Stars, Comparison and Check Stars

Abstract

Photometry from the Hipparcos catalogue is used to verify the constancy of four magnetic CP stars, as well as the comparison and the check stars used for variability studies of normal and chemically peculiar B and A stars with the Four College Automated Photoelectric Telescope; variability in these stars can produce spurious results. A few of the comparison stars are found to be variable and should be replaced for future differential photometric studies.