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.

恒星通常在簇中形成。由于它们的空间密度很高，因此簇中的恒星彼此接近凸起，直到簇在10^8-10^9年的时间尺度分解为止。在这样的初期阶段，行星可能会形成并受到恒星相遇的影响。我们特别研究了这些效果，表明Keiper带对象的轨道分布显示出此类相遇的标志。通过数值计算，我们表明，从太阳中经过约100个AU的一颗恒星可能导致40-47 au的当前Keiper皮带对象的高度偏心轨道，并抑制30 AU以上的大行星的形成，这与当前的太阳系相一致。超过30个AU，行星碰撞会导致破坏而不是吸收，从而形成灰尘碎屑盘。类似的灰尘生产过程也会在极性的行星系统中发生。观察结果表明，灰尘碎屑磁盘存在于中心恒星30个AU以上。我们的结果与观察结果一致。我们几次在美国天文学会的DPS会议上介绍了这些结果，并在DPS的杂志《 iCarus》中发表了两篇相关论文，并提交了另外两篇论文。