Summary: 1
THE CLASSIFICATION OF HELIUM­RICH HOT SUBDWARFS
Simon Jeffery
Armagh Observatory
Paul Harrison
School of Physics and Astronomy, St Andrews University
John Drilling
Department of Physics, Louisiana State University
Ulrich Heber
Astronomisches Institut, Univ. Erlangen, Dr. Remeis­Sternwarte, Bamberg
Sabine Moehler
Space Telescope Science Institute
ABSTRACT: We introduce a spectral classification system for helium­rich hot subdwarfs
based on 1.5 š A spectra of high S/N. Based on a small number of absorption line ratios, the
scheme is logically constructed and can be extended to similar spectra of all hot subdwarfs.
1 Introduction and Observations
Several objects identified in the PG survey were classified sdO(D), having strong He i lines
and weak or absent Balmer lines (Green et al. 1986). Moehler et al. (1990) designated these
stars sdB--He. A list complete to 1995, December was compiled by Jeffery et al. (1996). The
authors set out to discover how these objects are related to other early­type subluminous

Source: Armagh Observatory
Jeffery, Simon - Armagh Observatory

Collections: Physics