The standard candle aspect of carbon stars

¹ INAF, Osservatorio Astronomico di Roma, Viale del Parco Mellini 84, 00136 Roma, Italia e-mail: battinel@oarhp1.rm.astro.it
² Département de Physique, Université de Montréal, CP 6128, succursale centre-ville, Montréal, Québec H3C 3J7, Canada e-mail: demers@astro.umontreal.ca

Received: 3 May 2005
Accepted: 3 July 2005

Abstract

This paper represents the second part of our effort to summarise various aspects of our homogeneous survey of carbon stars in nearby galaxies. Here we investigate the relationships between the size of the C star populations and the luminosity of the parent galaxies. We also explore the constancy of for various metallicities and properties of the parent galaxies. We conclude that C stars are a viable standard candle for galaxies large enough to contain one hundred or more C stars. The application of narrow-band filters limits, however, the use of C stars as standard candles to no more than ~2 Mpc with currently available ground-based telescopes. Near-IR photometry from space observations can significantly push the limit of detectability of C stars thus making them an interesting alternative to the TRGB method.