A sequence of nitrogen-rich very red giants in the globular cluster NGC 1851

被引：11

作者：

Carretta, Eugenio ^{[1
]}

D'Orazi, Valentina ^{[2
,3
]}

Gratton, Raffaele G. ^{[4
]}

Lucatello, Sara ^{[4
]}

机构：

[1] INAF, Osservatorio Astron Bologna, I-40127 Bologna, Italy

[2] Macquarie Univ, Dept Phys & Astron, Sydney, NSW 2109, Australia

[3] Monash Univ, Sch Math Sci, Monash Ctr Astrophys, Clayton, Vic 3800, Australia

[4] INAF, Osservatorio Astron Padova, I-35122 Padua, Italy

来源：

ASTRONOMY & ASTROPHYSICS | 2014年 / 563卷

关键词：

stars: abundances; globular clusters: individual: NGC 1851; stars: Population II; globular clusters: general; stars: atmospheres; BRANCH STARS; ABUNDANCE VARIATIONS; STELLAR POPULATIONS; SUBGIANT BRANCH; MAIN-SEQUENCE; ORIGIN; INHOMOGENEITY;

D O I：

10.1051/0004-6361/201323023

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present the abundances of N in a sample of 62 stars on the red giant branch (RGB) in the peculiar globular cluster NGC 1851. The values of [N/Fe] ratio were obtained by comparing the flux measured in the observed spectra with that from synthetic spectra for up to about 15 features of CN. This is the first time that N abundances are obtained for such a large sample of RGB stars from medium-resolution spectroscopy in this cluster. With these abundances, we provide chemical tagging of the split RGB found from several studies in NGC 1851. The secondary reddest sequence on the RGB is populated almost exclusively by N-rich stars, confirming our previous suggestion based on Stromgren magnitudes and colours. These giants are also, on average, enriched in s-process elements such as Ba, and are likely the results of pollution from low-mass stars that experienced episodes of third dredge-up in the asymptotic giant branch phase.

引用

页数：5

共 28 条

[1]

Anderson J, 1998, THESIS U CALIFORNIA

[2] Origin of abundance inhomogeneity in globular clusters [J].

Bekki, K. ;

Campbell, S. W. ;

Lattanzio, J. C. ;

Norris, J. E. .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2007, 377 (01) :335-351

[3] CYANOGEN IN NGC 1851 RED GIANT BRANCH AND ASYMPTOTIC GIANT BRANCH STARS: QUADRIMODAL DISTRIBUTIONS [J].

Campbell, S. W. ;

Yong, D. ;

Wylie-de Boer, E. C. ;

Stancliffe, R. J. ;

Lattanzio, J. C. ;

Angelou, G. C. ;

D'Orazi, V. ;

Martell, S. L. ;

Grundahl, F. ;

Sneden, C. .

ASTROPHYSICAL JOURNAL LETTERS, 2012, 761 (01)

[4] Aluminum abundances of multiple stellar generations in the globular cluster NGC 1851 [J].

Carretta, E. ;

D'Orazi, V. ;

Gratton, R. G. ;

Lucatello, S. .

ASTRONOMY & ASTROPHYSICS, 2012, 543

[5] Multiple stellar populations in the globular cluster NGC 1851 [J].

Carretta, E. ;

Lucatello, S. ;

Gratton, R. G. ;

Bragaglia, A. ;

D'Orazi, V. .

ASTRONOMY & ASTROPHYSICS, 2011, 533

[6] ABUNDANCES FOR A LARGE SAMPLE OF RED GIANTS IN NGC 1851: HINTS FOR A MERGER OF TWO CLUSTERS? [J].

Carretta, E. ;

Gratton, R. G. ;

Lucatello, S. ;

Bragaglia, A. ;

Catanzaro, G. ;

Leone, F. ;

Momany, Y. ;

D'Orazi, V. ;

Cassisi, S. ;

D'Antona, F. ;

Ortolani, S. .

ASTROPHYSICAL JOURNAL LETTERS, 2010, 722 (01) :L1-L6

[7] Properties of stellar generations in globular clusters and relations with global parameters [J].

Carretta, E. ;

Bragaglia, A. ;

Gratton, R. G. ;

Recio-Blanco, A. ;

Lucatello, S. ;

D'Orazi, V. ;

Cassisi, S. .

ASTRONOMY & ASTROPHYSICS, 2010, 516

[8] Intrinsic iron spread and a new metallicity scale for globular clusters [J].

Carretta, E. ;

Bragaglia, A. ;

Gratton, R. ;

D'Orazi, V. ;

Lucatello, S. .

ASTRONOMY & ASTROPHYSICS, 2009, 508 (02) :695-706

[9]

Carretta E., 2012, A A, V550, pA34

[10] CALCIUM AND LIGHT-ELEMENTS ABUNDANCE VARIATIONS FROM HIGH-RESOLUTION SPECTROSCOPY IN GLOBULAR CLUSTERS [J].

Carretta, Eugenio ;

Bragaglia, Angela ;

Gratton, Raffaele ;

Lucatello, Sara ;

Bellazzini, Michele ;

D'Orazi, Valentina .

ASTROPHYSICAL JOURNAL LETTERS, 2010, 712 (01) :L21-L25

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