New asymptotic giant branch carbon stars in the galactic halo

SPRINGER has CopyrightInternational audienceFor the first time the data on the eight confirmed or candidate carbon (C) stars found mainly fromobjective-prism plates are presented. By using the Catalina database of lightcurves, we find that allthese stars are pulsating, allowing a distance to be estimated through the K-band Period-Luminosity(PL) relation. This relation does not depend on spectral type (M or C) and distances are reliable even forC candidates. Seven stars are more than 10 kpc from the galactic plane, suggesting they do not belong tothe galactic disk. We also find one star located at about 180 kpc from the Sun, being one of the mostdistant star in the Galaxy. Many of these new C stars are relatively blue. Some comments are alsoprovided on seven other known halo carbon stars for which either a pulsation period is obtained, orbecause they were not included in previous works on halo C stars