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Dust settling and growth in protoplanetary disks and its implication for formation of extrasolar planets

原行星盘中的尘埃沉降和生长及其对太阳系外行星形成的影响

基本信息

批准号：
16340054
负责人：
IDA Shigeru
金额：
$ 9.34万
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 (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

Planetary systems are formed in protoplanetary disks that are by-products of star formation. The disks consist of 98-99 wt.% of H-He gas and residual dust grains. The dust coagulates into planetesimals and the planetesimals accrete into terrestria planets and cores of jovian planets.In this study, we investigated details of processes from dust to planetesimals. Collisions between dust grains do not necessarily result in coalescence. The conditions for coalescence of disruption were derived by numerical simulations (Wada et al. 2007). Self-gravitational instability of dust to clumps (planetesimals) was also studied by N-body simulations (Michikoshi et al. 2007). On the other hands, assuming complete sticking of dust collisions, we simulated evolution of dust size distributions as functions of radius and height of disks to calculate dust radiation from the disks and compare the results with observational data (Tanaka et al. 2005). We found that dust radiation decays on timescales of million years by growth of dust, wchich means that the decay does not necessarily imply depletion of disk gas.We also discussed implication for radio observation. With the theoretical model, we found that "AKARI" space telescope can detect dust components of disks down to Moon mass and fixed the survey project based on it. We also developed pipelines for star/planet formation study with IDL. Furthermore, we found that high-precision images by ALMA can detect difference in dust growth between inner and outer disks.

行星系统是在原行星盘中形成的，原行星盘是恒星形成的副产品。这些圆盘由 98-99 wt.% 的 H-He 气体和残留的尘埃颗粒组成。尘埃凝结成星子，星子又聚积成类地行星和木星行星的核心。在这项研究中，我们研究了从尘埃到星子的过程的细节。尘埃颗粒之间的碰撞并不一定会导致聚结。破坏合并的条件是通过数值模拟得出的（Wada et al. 2007）。尘埃团块（星子）的自引力不稳定性也通过 N 体模拟进行了研究（Michikoshi 等人，2007 年）。另一方面，假设尘埃碰撞完全粘附，我们模拟尘埃尺寸分布随圆盘半径和高度的变化的演变，以计算圆盘的尘埃辐射，并将结果与观测数据进行比较（Tanaka et al. 2005）。我们发现尘埃辐射会随着尘埃的生长而在百万年的时间尺度上衰减，这意味着衰减并不一定意味着盘气体的耗尽。我们还讨论了对射电观测的影响。通过理论模型，我们发现“AKARI”太空望远镜可以探测小至月球质量的盘状尘埃成分，并据此确定了巡天项目。我们还利用 IDL 开发了用于恒星/行星形成研究的管道。此外，我们发现 ALMA 的高精度图像可以检测内外盘之间灰尘生长的差异。