Hot Horizontal-Branch Stars: The Ubiquitous Nature of the "Jump" in Stromgren u, Low Gravities, and the Role of Radiative Levitation of Metals

Preprint

8 May 1999

preprint
Published by arXiv in arXiv

https://doi.org/10.48550/arXiv.astro-ph/9903120

Abstract

A "jump" in the BHB distribution in the V, u-y CMD was recently detected in the GC M13. It is morphologically best characterized as a discontinuity in u, u-y, with stars in the range 11,500<Teff(K)11,500 K, dramatically enhancing their abundances in the atmospheres of BHB stars in the "critical" temperature region. Model atmospheres taking diffusion effects into account are badly needed, and will likely lead to better overall agreement between canonical evolutionary theory and observations for BHB stars.

Keywords

RADIATIVE LEVITATION
EVOLUTIONARY THEORY
UBIQUITOUS NATURE
MODEL ATMOSPHERES
GRAVITIES
BHB STARS
STARS
JUMP

All Related Versions

Version 1, 1999-03-09, ArXiv
Version 2, 1999-05-08, ArXiv
Published version: The Astrophysical Journal, 524 (1), 242.

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