Analysis on the Metal Abundance and Motion Property of GD-1 Star Streaming
Abstract
The star streaming plays an important role in the formation and development of galaxies, and the study of star streaming in the Milky Way will help us further explore the origin and evolution of the Milky Way. The spectrum data of LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope) DR6 and SDSS (Sloan Digital Sky Survey) DR12 were cross-matched with the astrometric data of Gaia (Global Astrometric Interferometer for Astrophysics) DR2, respectively, to obtain the data of proper motion, etc. By limiting the velocity space, geometric space and metal abundance of the GD-1 star streaming, we obtained a total of 157 member stars of the star streaming from LAMOST DR6 and SDSS DR12. The average metal abundance of GD-1 star streaming is [Fe/H]=$-2.16\pm0.10$ dex, the elongation of star streaming is about $80^\circ$. The high probability member stars of GD-1 star streaming given by predecessors were collected to form larger member samples for comparative analysis. The metal abundance distribution of the GD-1 star streaming is found to be low inside and high outside, the radial velocity distribution along the star streaming is characterized by large velocities at both ends and small velocities in the middle. The gap between $\phi_1=-20^\circ$ ($\phi_1$ is the horizontal coordinate of the GD-1 star streaming coordinate system) and $\phi_1=-60^\circ$ is due to the movement differences of member stars. According to the distribution of member stars and their velocity distribution property, it is speculated that the origin position of GD-1 star streaming is near $\phi_1=-40^\circ$.
- Publication:
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Acta Astronomica Sinica
- Pub Date:
- March 2021
- Bibcode:
- 2021AcASn..62...17W
- Keywords:
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- star streaming: motion;
- star streaming: stellar metallicity;
- globular cluster: disruption;
- observational data: LAMOST