Carbon star survey of Local Group galaxies ^*,**

X. Wolf-Lundmark-Melotte a galaxy with an extreme C/M ratio

¹ INAF, Osservatorio Astronomico di Roma Viale del Parco Mellini 84, 00136 Roma, Italia
² Département de Physique, Université de Montréal, CP 6128, Succursale Centre-Ville, Montréal, Québec H3C 3J7, Canada e-mail: demers@astro.umontreal.ca

Corresponding author: P. Battinelli, battinel@oarhp1.rm.astro.it

Received: 21 October 2003
Accepted: 26 November 2003

Abstract

We used the CFH12K wide field camera to survey the carbon star population of the Wolf-Lundmark-Melotte system using the CN–TiO technique. 149 C stars are identified with a mean , corresponding to , a mean luminosity similar to what we found in other irregular galaxies. Star counts in and around the main body of WLM reveal that its stellar distribution is quite elliptical (ϵ = 0.58) with major and minor axes of 26' and 11'. Comparison of the density profile of C stars and old red giants shows that their scale lengths differ by only 15% pointing to mixed populations. WLM is found to be unique among dwarf irregular galaxies by having essentially a handful of early-type AGB M stars thus leading to an extreme C/M ratio. We conclude that like NGC 3109, WLM is a disk shaped galaxy, seen at an inclination of and devoid of an extended spherical stellar halo.