A new calibration of the RGB Tip as a Standard Candle

2001/10/30 by M. Bellazzini, Michele Bellazzini, Bellazzini, Michele +6
Computer Science · Earth and Planetary Sciences · Engineering · Physics and Astronomy · #3D Surveying and Cultural Heritage #Advanced Measurement and Metrology Techniques #Astrophysics (astro-ph) #FOS: Physical sciences #Optical measurement and interference techniques #astro-ph

paper · pdf · doi:10.48550/arxiv.astro-ph/0110645

6 pages, 2 .ps figures, latex, hrd_pasp.sty macro included. To appear in "Observed HR diagrams and stellar evolution: the interplay between observational constraints and theory", (Coimbra, June, 2001) ASP Conf. Ser., 2001, T. Lejeune and J. Fernandes, eds

arxiv created 2001/10/30 · openalex publication_date 2001/10/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We have obtained an accurate estimate of the absolute I magnitude of the Tip of the Red Giant Branch (M_I(TRGB)) for the globular cluster Omega Cen, based \em (a) on the largest photometric database ever assembled for a globular, by Pancino et al. (2000), and \em (b) on a direct distance estimate for \omen, recently obtained by Thompson et al.(2001) from a detached eclipsing binary. The derived value M_I(TRGB) = -4.04± 0.12 provides, at present, the most accurate empirical zero-point for the calibration of the \mtip -- [Fe/H] relation, at [Fe/H] ~ -1.7.

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