Blue Supergiants as a Tool for Extragalactic Distances - Empirical Diagnostics
Abstract
Blue supergiant stars can be exceptionally bright objects in the optical, making them prime targets for the determination of extragalactic distances. I describe how their photometric and spectroscopic properties can be calibrated to provide a measurement of their luminosity. I first review two well-known techniques, the luminosity of the brightest blue supergiants and, with the aid of recent spectroscopic data, the equivalent width of the Balmer lines. Next I discuss some recent developments concerning the luminosity dependence of the wind momentum and of the flux-weighted gravity, which can provide, if properly calibrated, powerful diagnostics for the determination of the distance to the parent galaxies.
Cite
@article{arxiv.astro-ph/0301179,
title = {Blue Supergiants as a Tool for Extragalactic Distances - Empirical Diagnostics},
author = {Fabio Bresolin},
journal= {arXiv preprint arXiv:astro-ph/0301179},
year = {2015}
}
Comments
Invited review at the International Workshop on "Stellar Candles for the Extragalactic Distance Scale", held in Concepcion, Chile, December 9-11, 2002