TY - JOUR
T1 - Nitrogen abundances in giant stars of the globular cluster NGC 6752
AU - Yong, David
AU - Grundahl, Frank
AU - Johnson, Jennifer A.
AU - Asplund, Martin
PY - 2008/9/10
Y1 - 2008/9/10
N2 - We present N abundances for 21 bright giants in the globular cluster NGC 6752 based on high-resolution UVES spectra of the 3360 ÅNH 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.
AB - We present N abundances for 21 bright giants in the globular cluster NGC 6752 based on high-resolution UVES spectra of the 3360 ÅNH 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.
KW - Galaxy: abundances
KW - Globular clusters: individual (NGC 6752)
KW - Stars: abundances
UR - http://www.scopus.com/inward/record.url?scp=52049094134&partnerID=8YFLogxK
U2 - 10.1086/590658
DO - 10.1086/590658
M3 - Article
SN - 0004-637X
VL - 684
SP - 1159
EP - 1169
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
ER -