We present a detailed abundance analysis of giant stars in NGC 1978, a massive, intermediate-age stellar cluster in the Large Magellanic Cloud, characterized by a high ellipticity and suspected to have a metallicity spread. We analyzed 11 giants, all cluster members, by using high-resolution spectra acquired with UVES/FLAMES at the ESO Very Large Telescope. We find an iron content of [Fe/H] = -0.38 dex with very low sigma[Fe/H]=0.07 dex dispersion, a mean heliocentric radial velocity vr=293.1+/-0.9 km s-1, and a velocity dispersion sigmavr=3.1 km s-1, thus excluding the presence of a significant metallicity, as well as velocity, spread within the cluster.
Ferraro F.R., Mucciarelli A., Carretta E., Origlia L. (2006). On the Iron Content of NGC 1978 in the LMC: A Metal-rich, Chemically Homogeneous Cluster. THE ASTROPHYSICAL JOURNAL, 645, L33-L36 [10.1086/506178].
On the Iron Content of NGC 1978 in the LMC: A Metal-rich, Chemically Homogeneous Cluster
FERRARO, FRANCESCO ROSARIO;MUCCIARELLI, ALESSIO;
2006
Abstract
We present a detailed abundance analysis of giant stars in NGC 1978, a massive, intermediate-age stellar cluster in the Large Magellanic Cloud, characterized by a high ellipticity and suspected to have a metallicity spread. We analyzed 11 giants, all cluster members, by using high-resolution spectra acquired with UVES/FLAMES at the ESO Very Large Telescope. We find an iron content of [Fe/H] = -0.38 dex with very low sigma[Fe/H]=0.07 dex dispersion, a mean heliocentric radial velocity vr=293.1+/-0.9 km s-1, and a velocity dispersion sigmavr=3.1 km s-1, thus excluding the presence of a significant metallicity, as well as velocity, spread within the cluster.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
