SCYON Abstract

Received on February 10 2006

The metallicity of the old open cluster NGC 6791

AuthorsRaffaele Gratton (1), Angela Bragaglia (2), Eugenio Carretta (2), Monica Tosi (2)
Affiliation
(1) INAF-Osservatorio Astronomico di Padova
(2) INAF-Osservatorio Astronomico di Bologna
Accepted byAstrophysical Journal
Contactangela.bragaglia@oabo.inaf.it
URLhttp://babbage.sissa.it/abs/astro-ph/0601027
Links NGC 6791

Abstract

We have observed four red clump stars in the very old and metal-rich open cluster NGC 6791 to derive its metallicity, using the high resolution spectrograph SARG mounted on the TNG. Using a spectrum synthesis technique we obtain an average value of [Fe/H] = +0.47 (+/- 0.04, rms=0.08) dex. Our method was tested on μ Leo, a well studied metal-rich field giant. We also derive average oxygen and carbon abundances for NGC 6791 from synthesis of [O I] at 6300 A and C2 at 5086 A, finding [O/Fe]@-0.3 and [C/Fe]@-0.2.