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The effects of passing stellar encounters on planet formation and implications to formation of dust debris disk around main sequence stars

恒星相遇对行星形成的影响以及对主序恒星周围尘埃碎片盘形成的影响

基本信息

批准号：
13640234
负责人：
IDA Shigeru
金额：
$ 1.98万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640234/
关键词：
Solar system planetesimals planet formation celestial mechanics star formation dust debris disk collisional disruption

项目摘要

Stars are generally formed in clusters. Since their spatial density is high, stars in clusters experience close concounters with each other until the clusters are broken up on timescales of 10^8-10^9 years. In such initial stages, planets are likely to be being formed and be affected by the stellar encounters. We have investigated the effects, in particular, suggested that the orbital distribution of Keiper belt objects show signature of such encounters. Through numerical calculations, we showed that a star passing through about 100 AU from the Sun can be responsible for the highly eccentric orbits of current Keiper belt objects at 40-47 AU and inhibit formation of large planets beyond 30 AU, which is consistenet with present Solar system. Beyond 30 AU, collisions of planetesimals result in disruption rather than accretion, resulting in formation of a dust debris disk. Similar dust production processes would occur also in extrasolar planetary systems. Observations show that dust debris disks exist beyond 30 AU from central stars. Our result is consistent with the observations. We have presented these results at DPS meetings of American Astronomical Society a few times, and published two related papers in DPS' s journal "Icarus" and submitted another two papers.

恒星通常是在星团中形成的。由于它们的空间密度很高，星团中的恒星会经历彼此的近距离接触，直到星团在10^8-10^9年的时间尺度上分裂。在这样的初始阶段，行星很可能正在形成，并受到恒星碰撞的影响。我们已经研究了这种影响，特别指出，柯伊伯带天体的轨道分布显示出这种遭遇的特征。通过数值计算，我们发现，一颗恒星经过距离太阳约100 AU的地方，可以导致目前40-47 AU的凯伯带天体的高偏心轨道，并抑制30 AU以上的大行星的形成，这与现在的太阳系一致。超过30天文单位，星子的碰撞导致的是破坏而不是吸积，从而形成了尘埃碎片盘。类似的尘埃产生过程也会发生在太阳系外的行星系统中。观测显示，在距离中心恒星30天文单位以外的地方存在尘埃碎片盘。我们的结果与观测结果一致。我们在美国天文学会的DPS会议上多次展示了这些结果，并在DPS的期刊《伊卡洛斯》上发表了两篇相关论文，并提交了另外两篇论文。