2002/10/07 by Bradford Behr, Bradford B. Behr, Behr, Bradford
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0210163
8 pages, 2 figures, uses newpasp.sty (included), to appear in "New Horizons in Globular Cluster Astronomy", eds. G. Piotto, G. Meylan, G. Djorgovski, & M. Riello, ASP Conf. Ser. (2003)
arxiv created 2002/10/07 · openalex publication_date 2002/10/07 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
To address the puzzling photometric properties of horizontal branch stars in Galactic GCs, several different groups have undertaken detailed spectroscopic analyses of individual blue HB stars. Hotter BHB stars show strong metal enhancement and helium depletion, likely due to atomic diffusion, and slow rotation velocities, in contrast to the cooler BHB stars, which have a bimodal distribution of rotation speeds -- some of them much faster than expected -- but no anomalous abundances. I review the observational results to date, and discuss possible explanations and ramifications of these abundance and rotation characteristics.