Chemical Abundances of the Highly Obscured Galactic Globular Clusters 2MASS GC02 and Mercer 5

Peñaloza, F.; Pessev, P.; Vaśquez, Sergio; Borissova, Jura; Kurtev, Radostin; Zoccali, Manuela
Bibliographical reference

Publications of the Astronomical Society of the Pacific, Volume 127, issue 950, pp.329-339

Advertised on:
4
2015
Number of authors
6
IAC number of authors
1
Citations
8
Refereed citations
8
Description
We present the first high spectral resolution abundance analysis of two newly discovered Galactic globular clusters, namely, Mercer 5 and 2MASS GC02, residing in regions of high interstellar reddening in the direction of the Galactic center. The data were acquired with the Phoenix high-resolution near-infrared echelle spectrograph at Gemini South (R ˜ 50,000) in the 15,500.0-15,575.0 spectral region. Iron, oxygen, silicon, titanium, and nickel abundances were derived for two red giant stars, in each cluster, by comparing the entire observed spectrum with a grid of synthetic spectra generated with MOOG. We found [Fe/H] values of -0.86 ± 0.12 and -1.08 ± 0.13 for Mercer 5 and 2MASS GC02, respectively. The [O/Fe], [Si/Fe], and [Ti/Fe] ratios of the measured stars of Mercer 5 follow the general trend of both bulge field and cluster stars at this metallicity, and are enhanced by ≥+0.3. The 2MASS GC02 stars have relatively lower ratios, but still compatible with other bulge clusters. Based on metallicity and abundance patterns of both objects, we conclude that these are typical bulge globular clusters.
Type