| On the minimum mass ratio of W UMa binaries | |
Jiang DK(姜登凯)1,2,3 ; Han ZW(韩占文)1,3; Wang JC(王建成)1,3; Jiang TY(姜天雨)1,2,3; Li LF(李立芳)1,3; Jiang, DK (reprint author), Chinese Acad Sci, Yunnan Observ, Natl Astron Observ, POB 110, Kunming 650011, Yunnan Province, Peoples R China.
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| 发表期刊 | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
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| 2010-07-11 | |
| 卷号 | 405期号:4页码:2485-2491 |
| DOI | 10.1111/j.1365-2966.2010.16615.x |
| 产权排序 | 第1完成单位 |
| 收录类别 | SCI |
| 关键词 | Instabilities Binaries: Close Blue Stragglers Stars: Evolution Stars: Rotation |
| 摘要 | Using Eggleton's stellar evolution code, we study the minimum mass ratio (q(min)) of W Ursae Majoris (W UMa) binaries that have different primary masses. It is found that the minimum mass ratio of W UMa binaries decreases with increasing mass of the primary if the primary's mass is less than about 1.3 M(circle dot), while above this mass the ratio is roughly constant. By comparing the theoretical minimum mass ratio with observational data, it is found that the existence of low-q systems can be explained by the different structure of primaries with different masses. This suggests that the dimensionless gyration radius (k2(1)) and thus the structure of the primary is very important in determining the minimum mass ratio. In addition, we investigate the mass loss during the merging process of W UMa systems and calculate the rotation velocities of the single stars formed by mergers of W UMa binaries due to tidal instability. It is found that in the case of conservation of mass and angular momentum, the merged single stars rotate with an equatorial velocity of about similar to 588-819 km s-1, which is much larger than their break-up velocities (v(b)). This suggests that the merged stars should extend to a very large radius (similar to 3.7-5.3 times the radii of the primaries) or else W UMa systems should lose a large amount of mass (similar to 21-33 per cent of the total mass) during the merging process. If the effect of magnetic braking is considered, the mass loss decreases to similar to 12-18 per cent of the total mass. This implies that significant angular momentum and mass might be lost from W UMa systems in the course of the merging process, and this kind of mass and angular momentum loss might be driven by the release of orbital energy of the secondaries, similarly to common-envelope evolution. |
| 项目资助者 | Chinese Natural Science Foundation [10673029, 10773026, 10521001, 2007CB815406, 10821061] ; Foundation of Chinese Academy of Sciences [KJCX2-YW-T24] ; Yunnan Natural Science Foundation [2007A113M] |
| 语种 | 英语 |
| 学科领域 | Astronomy & Astrophysics |
| 文章类型 | Article |
| ISSN | 0035-8711 |
| URL | 查看原文 |
| 归档日期 | 2010-07-13 |
| WOS记录号 | WOS:000279450900029 |
| WOS研究方向 | Astronomy & Astrophysics |
| WOS类目 | Astronomy & Astrophysics |
| 关键词[WOS] | MAJORIS-TYPE SYSTEMS ; COMMON-ENVELOPE EVOLUTION ; WUMA-TYPE BINARIES ; CONTACT BINARIES ; BLUE-STRAGGLERS ; URSAE-MAJORIS ; PHYSICAL PARAMETERS ; ECLIPSING BINARIES ; STELLAR EVOLUTION ; GLOBULAR-CLUSTERS |
| 引用统计 | |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://ir.ynao.ac.cn/handle/114a53/4495 |
| 专题 | 大样本恒星演化研究组 中国科学院天体结构与演化重点实验室 |
| 通讯作者 | Jiang, DK (reprint author), Chinese Acad Sci, Yunnan Observ, Natl Astron Observ, POB 110, Kunming 650011, Yunnan Province, Peoples R China. |
| 作者单位 | 1.National Astronomical Observatories, Yunnan Observatory, Chinese Academy of Sciences, PO Box 110, Kunming, Yunnan Province 650011, China 2.Graduate University of Chinese Academy of Sciences, Beijing 100039, China 3.Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011, China |
| 第一作者单位 | 中国科学院云南天文台 |
| 推荐引用方式 GB/T 7714 | Jiang DK,Han ZW,Wang JC,et al. On the minimum mass ratio of W UMa binaries[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2010,405(4):2485-2491. |
| APA | Jiang DK,Han ZW,Wang JC,Jiang TY,Li LF,&Jiang, DK .(2010).On the minimum mass ratio of W UMa binaries.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,405(4),2485-2491. |
| MLA | Jiang DK,et al."On the minimum mass ratio of W UMa binaries".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 405.4(2010):2485-2491. |
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| On the minimum mass （581KB） | 期刊论文 | 作者接受稿 | 开放获取 | CC BY-NC-SA | 浏览 请求全文 | |
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