HD Stars South of δ = −53° Having Peculiar Abundances: Statistics and Notation

Abstract

The HD stars between δ = −90° and −53° have been classified on the MK system, using Michigan 4° +6° objective-prism Schmidt plates (108 Å mm⁻¹) taken at Cerro Tololo, Chile, and the results are published in Vol. 1 of the University of Michigan Catalogue, Catalogue of Two-Dimensional Types for the HD Stars. First, various statistics on the 32 500 normal stars and 2500 peculiar stars found are presented. Peculiar/normal ratios for various types of stars are given, along with discussion of the assumptions made. About 40% of the peculiar stars are of the Am or Ap types, and these will be covered in detail. Secondly, what notation to use for spectral types of stars with peculiar abundances is discussed and an explanation given of the notation used in Vol. 1 of the Michigan Catalogue for Am, Ap, strong and weak CN, weak metal, and other categories of peculiar stars.