Vol 17, No 7 (2017) / Ren

The metallicity of K giant stars along the Sagittarius streams

Hong-Bo Ren, Wei-Bin Shi, Xu Zhang, Yan-Ke Tang, Yong Zhang, Yong-Hui Hou, Yue-Fei Wang


The Large Sky-Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Data Release 3 provided 341 691 K giant stars with stellar parameters. Based on the models of Law & Majewski, we identified 252 K giant stars in the leading stream associated with the Sagittarius (Sgr) dwarf galaxy. We obtained 132 K giant stars belonging to the trailing arm of Sgr using the model of Belokurov et al. We studied the metallicity distribution of member stars along the streams and found a flat gradient in the first wrap of the leading stream, –(0.88±0.3) × 10 −3 dex/(°) in the second wrap of the leading stream and –(1.2±0.3) × 10−3 dex/(°) in the first wrap of the trailing stream. Moreover, we obtained a combined metallicity gradient with our sample and data from the literature. We also analyzed the properties of an overdensity, which is located in the leading stream of the Sgr.


Galaxy: halo — galaxies: individual (Sagittarius) — stars: K giant-branch

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DOI: https://doi.org/10.1088/1674–4527/17/7/76


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