SCYON Abstract

Received on September 26 2006

Deep FORS1 observations of the double Main Sequence of omega Centauri

AuthorsA. Sollima (1), F.R. Ferraro (1), M. Bellazzini (2), L. Origlia (2), O. Straniero (3), and E. Pancino (2)
Affiliation
(1) Universita' di Bologna
(2) INAF Osservatorio Astronomico di Bologna
(3) INAF Osservatorio Astronomico di Collurania, Teramo
Accepted byAstrophysical Journal
Contactantonio.sollima@bo.astro.it
URLhttp://www.arxiv.org/abs/astro-ph/0609650
Links

Abstract

We present the results of a deep photometric survey performed with FORS1@VLT aimed at investigating the complex Main Sequence structure of the stellar system omega Centauri. We confirm the presence of a double Main Sequence and identify its blue component (bMS) over a large field of view up to 26' from the cluster center. We found that bMS stars are significantly more concentrated toward the cluster center than the other "normal" MS stars. The bMS morphology and its position in the CMD have been used to constrain the helium overabundance required to explain the observed MS morphology.