A DOUBLE MAIN SEQUENCE IN THE GLOBULAR CLUSTER NGC 6397

被引：93

作者：

Milone, A. P. ^{[1
,2
]}

Marino, A. F. ^{[3
]}

Piotto, G. ^{[4
,5
]}

Bedin, L. R. ^{[6
]}

Anderson, J. ^{[6
]}

Aparicio, A. ^{[1
,2
]}

Cassisi, S. ^{[7
]}

Rich, R. M. ^{[8
]}

机构：

[1] Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Tenerife, Spain

[2] Univ La Laguna, Dept Astrophys, E-38200 San Cristobal la Laguna, Tenerife, Spain

[3] Max Planck Inst Astrophys, D-85741 Garching, Germany

[4] Univ Padua, Dipartimento Astron, I-35122 Padua, Italy

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

[6] Space Telescope Sci Inst, Baltimore, MD 21218 USA

[7] INAF Osservatorio Astron Collurania, I-64100 Teramo, Italy

[8] Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA

来源：

ASTROPHYSICAL JOURNAL | 2012年 / 745卷 / 01期

关键词：

globular clusters: individual (NGC 6397); stars: Population II; MULTIPLE STELLAR POPULATIONS; ADVANCED CAMERA; OMEGA-CENTAURI; GIANT STARS; ACS SURVEY; ABUNDANCES; NGC-6397; BRANCH; ASTROMETRY; NGC-2808;

D O I：

10.1088/0004-637X/745/1/27

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

High-precision multi-band Hubble Space Telescope (HST) photometry reveals that the main sequence of the globular cluster NGC 6397 splits into two components, containing similar to 30% and similar to 70% of the stars. This double sequence is consistent with the idea that the cluster hosts two stellar populations: (1) a primordial population that has a composition similar to field stars, containing similar to 30% of the stars, and (2) a second generation with enhanced sodium and nitrogen, depleted carbon and oxygen, and a slightly enhanced helium abundance (Delta Y similar to 0.01). We examine the color difference between the two sequences across a variety of color baselines and find that the second sequence is anomalously faint in m(F336W). Theoretical isochrones indicate that this could be due to NH depletion.

引用

页数：10

共 49 条

[21] Abundance variations within globular clusters [J].

Gratton, R ;

Sneden, C ;

Carretta, E .

ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, 2004, 42 :385-440

[22] The O-Na and Mg-Al anticorrelations in turn-off and early subgiants in globular clusters [J].

Gratton, RG ;

Bonifacio, P ;

Bragaglia, A ;

Carretta, E ;

Castellani, V ;

Centurion, M ;

Chieffi, A ;

Claudi, R ;

Clementini, G ;

D'Antona, F ;

Desidera, S ;

François, P ;

Grundahl, F ;

Lucatello, S ;

Molaro, P ;

Pasquini, L ;

Sneden, C ;

Spite, F ;

Straniero, O .

ASTRONOMY & ASTROPHYSICS, 2001, 369 (01) :87-98

[23]

Harris W. E., 2010, ARXIV10123224

[24] A catalog of parameters for globular clusters in the Milky Way [J].

Harris, WE .

ASTRONOMICAL JOURNAL, 1996, 112 (04) :1487-1488

[25] NONHOMOGENEITY OF METAL ABUNDANCES IN STARS OF GLOBULAR-CLUSTERS AND SATELLITE SUBSYSTEMS OF THE GALAXY [J].

KRAFT, RP .

ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, 1979, 17 :309-343

[26]

Kurucz R.L., 2005, Mem. Soc. Astron. Ital. Suppl, V8, P14

[27] Enrichment by supernovae in globular clusters with multiple populations [J].

Lee, Jae-Woo ;

Kang, Young-Woon ;

Lee, Jina ;

Lee, Young-Wook .

NATURE, 2009, 462 (7272) :480-482

[28] Tracing the evolution of NGC 6397 through the chemical composition of its stellar populations [J].

Lind, K. ;

Charbonnel, C. ;

Decressin, T. ;

Primas, F. ;

Grundahl, F. ;

Asplund, M. .

ASTRONOMY & ASTROPHYSICS, 2011, 527

[29] Signatures of intrinsic Li depletion and Li-Na anti-correlation in the metal-poor globular cluster NGC 6397 [J].

Lind, K. ;

Primas, F. ;

Charbonnel, C. ;

Grundahl, F. ;

Asplund, M. .

ASTRONOMY & ASTROPHYSICS, 2009, 503 (02) :545-557

[30] Spectroscopic and photometric evidence of two stellar populations in the Galactic globular cluster NGC 6121 (M 4) [J].

Marino, A. F. ;

Villanova, S. ;

Piotto, G. ;

Milone, A. P. ;

Momany, Y. ;

Bedin, L. R. ;

Medling, A. M. .

ASTRONOMY & ASTROPHYSICS, 2008, 490 (02) :625-640

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