BLUE STRAGGLER EVOLUTION CAUGHT IN THE ACT IN THE LARGE MAGELLANIC CLOUD GLOBULAR CLUSTER HODGE 11

被引:15
作者
Li, Chengyuan [1 ,2 ,3 ]
de Grijs, Richard [1 ,2 ]
Deng, Licai [3 ]
Liu, Xiangkun [1 ,2 ]
机构
[1] Peking Univ, Kavli Inst Astron & Astrophys, Beijing 100871, Peoples R China
[2] Peking Univ, Dept Astron, Beijing 100871, Peoples R China
[3] Chinese Acad Sci, Key Lab Opt Astron, Natl Astron Observ, Beijing 100012, Peoples R China
基金
中国国家自然科学基金;
关键词
blue stragglers; galaxies: star clusters: individual (Hodge 11); Hertzsprung-Russell and C-M diagrams; Magellanic Clouds; stars: kinematics and dynamics; SPACE-TELESCOPE OBSERVATIONS; STELLAR COLLISIONS; STAR-CLUSTERS; RADIAL-DISTRIBUTION; MASS SEGREGATION; MAIN-SEQUENCE; POPULATION; SPECTROSCOPY; SIMULATIONS; ISOCHRONES;
D O I
10.1088/2041-8205/770/1/L7
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
High-resolution Hubble Space Telescope imaging observations show that the radial distribution of the field-decontaminated sample of 162 "blue straggler" stars (BSs) in the 11.7(-0.1)(+0.2) Gyr old Large Magellanic Cloud cluster Hodge 11 exhibits a clear bimodality. In combination with their distinct loci in color-magnitude space, this offers new evidence in support of theoretical expectations that suggest different BS formation channels as a function of stellar density. In the cluster's color-magnitude diagram, the BSs in the inner 15 '' (roughly corresponding to the cluster's core radius) are located more closely to the theoretical sequence resulting from stellar collisions, while those in the periphery (at radii between 85 '' and 100 '') are preferentially found in the region expected to contain objects formed through binary mass transfer or coalescence. In addition, the objects' distribution in color-magnitude space provides us with the rare opportunity in an extragalactic environment to quantify the evolution of the cluster's collisionally induced BS population and the likely period that has elapsed since their formation epoch, which we estimate to have occurred similar to 4-5 Gyr ago.
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页数:6
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