The Peculiar Horizontal Branch Morphology of the Galactic Globular Clusters NGC6388 and NGC6441

2007/12/21 by G. Busso, Busso, Giorgia
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Stellar, planetary, and galactic studies

paper · pdf · doi:10.48550/arxiv.0712.3720

openalex publication_date 2007/12/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

I present multiband optical and UV Hubble Space Telescope photometry of the two Galactic globular clusters NGC6388 and NGC6441, in order to investigate the nature of the physical mechanism(s) responsible for the existence of an extended blue tail and of a slope in the horizontal branch. Further evidence that the horizontal branch tilt cannot be interpreted as an effect of differential reddening is provided, while I show that a possible solution of the puzzle is to assume that a small fraction of the stellar population in the two clusters is strongly helium enriched.

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