A WFC3/HST VIEW OF THE THREE STELLAR POPULATIONS IN THE GLOBULAR CLUSTER NGC 6752

被引：143

作者：

Milone, A. P. ^{[1
,2
,3
]}

Marino, A. F. ^{[1
,4
]}

Piotto, G. ^{[5
,6
]}

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

Anderson, J. ^{[7
]}

Aparicio, A. ^{[2
,3
]}

Bellini, A. ^{[7
]}

Cassisi, S. ^{[8
]}

D'Antona, F. ^{[9
]}

Grundahl, F. ^{[10
]}

Monelli, M. ^{[2
,3
]}

Yong, D. ^{[1
]}

机构：

[1] Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia

[2] Inst Astrofis Canarias, E-38200 Tenerife, Canary Islands, Spain

[3] Univ La Laguna, Dept Astrophys, E-38200 Tenerife, Canary Islands, Spain

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

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

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

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

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

[9] INAF Osservatorio Astron Roma, I-00040 Rome, Italy

[10] Aarhus Univ, Dept Phys & Astron, DK-8000 Aarhus C, Denmark

来源：

ASTROPHYSICAL JOURNAL | 2013年 / 767卷 / 02期

基金：

澳大利亚研究理事会;

关键词：

globular clusters: individual (NGC 6752); stars: Population II; HORIZONTAL-BRANCH STARS; MAIN-SEQUENCE TURNOFF; NA-O ANTICORRELATION; OMEGA-CENTAURI; MULTIPLE POPULATIONS; GIANT BRANCH; 47; TUCANAE; ACS SURVEY; CYANOGEN DISTRIBUTION; ABUNDANCE VARIATIONS;

D O I：

10.1088/0004-637X/767/2/120

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Multi-band Hubble Space Telescope photometry reveals that the main sequence, sub-giant, and the red-giant branch of the globular cluster NGC 6752 splits into threemain components in close analogy with the three distinct segments along its horizontal branch stars. These triple sequences are consistent with three stellar groups: a stellar population with a chemical composition similar to field-halo stars (Population a), a Population (c) with enhanced sodium and nitrogen, depleted carbon and oxygen, and an enhanced helium abundance (Delta Y similar to 0.03), and a Population (b) with an intermediate (between Populations a and c) chemical composition and slightly enhanced helium (Delta Y similar to 0.01). These components contain similar to 25% (Population a), similar to 45% (Population b), and similar to 30% (Population c) of the stars. No radial gradient for the relative numbers of the three populations has been identified out to about 2.5 half-mass radii.

引用

页数：20

共 85 条

[1]

Anderson A. J., 1997, PhD thesis

[2] Ground-based CCD astrometry with wide field imagers - I. Observations just a few years apart allow decontamination of field objects from members in two globular clusters [J].