Hercules and Wolf 630 stellar streams and galactic bar kinematics

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• 作者：V. V. Bobylev ; A. T. Bajkova
• 刊名：Astronomy Letters
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：42
• 期：4
• 页码：228-239
• 全文大小：1,195 KB
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics
  Astronomy
  Astrophysics
  Russian Library of Science
  
• 出版者：MAIK Nauka/Interperiodica distributed exclusively by Springer Science+Business Media LLC.
• ISSN：1562-6873
• 卷排序：42

文摘

We have identified the four most significant features in the UV velocity distribution of solarneighborhood stars: H1, H2 in the Hercules stream and W1, W2 in the Wolf 630 stream. We have formulated the problemof determining several characteristics of the centralGalactic bar independently from each of the identified features by assuming that the Hercules and Wolf 630 streams are of a bar-induced dynamical nature. The problem has been solved by constructing 2: 1 resonant orbits in the rotating bar frame for each star in these streams. Analysis of the resonant orbits found has shown that the bar pattern speed is 45–55 km s−1 kpc−1, while the bar angle lies within the range 40°−60°. The results obtained are consistent with the view that the Hercules andWolf 630 streams could be formed by a long-term influence of the Galactic bar leading to a characteristic bimodal splitting of the UV velocity plane.Keywordskinematicsstellar streamsWolf 630 streamHercules streamGalactic barGalaxy (Milky Way)