A DOUBLE MAIN SEQUENCE IN THE GLOBULAR CLUSTER NGC 6397

被引：90

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 50 条

[21] HST OBSERVATIONS OF THE CORE OF GLOBULAR-CLUSTER NGC 6397
BURGARELLA, D
PARESCE, F
MEYLAN, G
KING, IR
GREENFIELD, P
BAXTER, D
JEDRZEJEWSKI, R
NOTA, A
ALBRECHT, R
BARBIERI, C
BLADES, JC
BOKSENBERG, A
CRANE, P
DEHARVENG, JM
DISNEY, MJ
JAKOBSEN, P
KAMPERMAN, TM
MACCHETTO, F
MACKAY, CD
WEIGELT, G
ASTRONOMY & ASTROPHYSICS, 1994, 287 (03) : 769 - 781
[22] HORIZONTAL-BRANCH STARS OF GLOBULAR CLUSTER NGC 6397
SEARLE, L
RODGERS, AW
ASTROPHYSICAL JOURNAL, 1966, 143 (03): : 809 - &
[23] Far-ultraviolet observation of the globular cluster NGC 6397
Dieball, A.
Rasekh, A.
Knigge, C.
Shara, M.
Zurek, D.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2017, 469 (01) : 267 - 277
[24] HST observations of white dwarfs in the globular cluster NGC 6397
Astrophys Space Sci Libr, 214 (129):
[25] VLT observations of turnoff stars in the globular cluster NGC 6397
Thévenin, F
Charbonnel, C
Pacheco, AJD
Idiart, TP
Jasniewicz, G
de Laverny, P
Plez, B
ASTRONOMY & ASTROPHYSICS, 2001, 373 (03) : 905 - 915
[26] HST observations of white dwarfs in the globular cluster NGC 6397
Cool, AM
Sosin, C
King, IR
WHITE DWARFS, 1997, 214 : 129 - 134
[27] On the radial distribution of white dwarfs in the globular cluster NGC 6397
Davis, D. S.
Richer, H. B.
King, I. R.
Anderson, J.
Coffey, J.
Fahlman, G. G.
Hurley, J.
Kalirai, J. S.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2008, 383 (01) : L20 - L24
[28] THE MAIN-SEQUENCE OF THE GLOBULAR-CLUSTER NGC-3201
ALCAINO, G
LILLER, W
ASTRONOMICAL JOURNAL, 1981, 86 (10): : 1480 - 1499
[29] MAIN-SEQUENCE OF THE GLOBULAR-CLUSTER NGC-6752
CARNEY, BW
ASTRONOMICAL JOURNAL, 1979, 84 (04): : 515 - &
[30] THE MAIN-SEQUENCE OF THE GLOBULAR-CLUSTER NGC-288
ALCAINO, G
LILLER, W
ASTRONOMICAL JOURNAL, 1980, 85 (12): : 1592 - 1603

← 1 2 3 4 5 →