Nitrogen Abundances in Giant Stars of the Globular Cluster NGC 6752
Abstract
We present N abundances for 21 bright giants in the globular cluster NGC 6752 based on high-resolution UVES spectra of the 3360 Å NH lines. We confirm that the Strömgren c1 index traces the N abundance and find that the star-to-star N abundance variation is 1.95 dex, at the sample's luminosity. We find statistically significant correlations, but small-amplitude variations, between the abundances of N and α-, Fe-peak, and s-process elements. Analyses using model atmospheres with appropriate N, O, Na, and Al abundances would strengthen, rather than mute, these correlations. If the small variations of heavy elements are real, then the synthesis of the N anomalies must take place in stars which also synthesize α-, Fe-peak, and s-process elements. These correlations offer support for contributions from both asymptotic giant branch and massive stars to the globular cluster abundance anomalies.
Based on observations made with ESO Telescopes at the Paranal Observatories under program 65.L-0165(A).- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 2008
- DOI:
- 10.1086/590658
- arXiv:
- arXiv:0806.0187
- Bibcode:
- 2008ApJ...684.1159Y
- Keywords:
-
- Galaxy: abundances;
- globular clusters: individual: NGC 6752;
- stars: abundances;
- Astrophysics
- E-Print:
- Accepted for publication in ApJ