Ages of globular clusters: A new approach

被引:74
作者
Jimenez, R
Thejll, P
Jorgensen, UG
MacDonald, J
Pagel, B
机构
[1] NIELS BOHR INST,DK-2100 COPENHAGEN,DENMARK
[2] UNIV DELAWARE,DEPT PHYS & ASTRON,NEWARK,DE 19716
关键词
stars; evolution; horizontal branch; mass-loss; globular clusters; general; cosmology; miscellaneous;
D O I
10.1093/mnras/282.3.926
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We have used a new method to analyse the horizontal branch (HE) morphology in relation to the distribution of stars near the red giant branch (RGB) tip for the globular clusters M22, M5, M68, M107, M72, M92, M3 and 47 Tuc, This new method permits the determination of the cluster ages to greater accuracy than does conventional isochrone fitting, Using the method in conjunction with our new high-quality photometric data for RGB and HE stars in the first five of these clusters, we discuss the origins of the spread in colour on the HB and its relation to the 'second parameter' problem. The oldest clusters in our sample are found to have relatively low ages (13.5 +/- 2 Gyr). A 1 sigma uncertainty in each of the parameters of mass and helium content, combined with the effects of helium diffusion, gives a lower limit for the age of the oldest clusters of 9.7 Gyr.
引用
收藏
页码:926 / 942
页数:17
相关论文
共 88 条
[1]  
ALCAINO G, 1983, AJ, V88, P130
[2]  
ALCAINO G, 1990, AJ, V93, P114
[3]   COLOR-MAGNITUDE DIAGRAM FOR THE GLOBULAR CLUSTER M22 [J].
ARP, HC ;
MELBOURNE, WG .
ASTRONOMICAL JOURNAL, 1959, 64 (01) :28-32
[5]   OXYGEN-ENHANCED MODELS FOR GLOBULAR-CLUSTER STARS .2. ISOCHRONES AND LUMINOSITY FUNCTIONS [J].
BERGBUSCH, PA ;
VANDENBERG, DA .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1992, 81 (01) :163-220
[6]  
Bohm-Vitense E., 1958, Z ASTROPHYS, V46, p[108, 108]
[7]  
BUONANNO R, 1985, ASTRON ASTROPHYS, V145, P97
[8]  
Buonanno R., 1983, Astronomy & Astrophysics Supplement Series, V53, P1
[9]   ON THE GIANT, ASYMPTOTIC AND HORIZONTAL BRANCHES OF GLOBULAR-CLUSTERS .1. PHOTOGRAPHIC PHOTOMETRY OF M5 [J].
BUONANNO, R ;
CORSI, CE ;
PECCI, FF .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1981, 196 (02) :435-454
[10]  
Buonanno R., 1986, MEM SOC ASTRON ITAL, V57, P391