A Search for Red Variable Stars in the LMC

Abstract

The observational material for this study consists of a series of 19 I plates (IVN+RG715) of the southern half of the LMC taken by the UK Schmidt Telescope over a six year period from 1977–1983. A small region of size 28′x56′ centred on α(1950) = 5 28 50.7, δ(1950) = −69 31 56 was scanned on all plates with a PDS microdensitometer and magnitudes were derived for typically 14000 stars per scan area. All magnitudes were converted to a common system by comparison of magnitudes to a standard plate; this comparison showed the individual rms measurement error to be 0.13 mag. No photoelectric standard sequence exists in the region studied but the instrumental magnitudes have been converted to preliminary IK magnitudes by using the IK magnitudes given by Blanco, McCarthy and Blanco (1980) for some of the red stars in the field.