Insights into Planet Formation from Debris Disks
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- 作者：Mark C. Wyatt ; Alan P. Jackson
- 关键词：Circumstellar disks ; Planet formation
- 刊名：Space Science Reviews
- 出版年：2016
- 出版时间：December 2016
- 年：2016
- 卷：205
- 期：1-4
- 页码：231-265
- 全文大小：2858KB
- 刊物类别：Physics and Astronomy
- 刊物主题：Space Sciences (including Extraterrestrial Physics, Space Exploration and Astronautics); Planetology; Aerospace Technology and Astronautics; Astrophysics and Astroparticles;
- 出版者：Springer Netherlands
- ISSN：1572-9672
- 卷排序：205
文摘
Giant impacts refer to collisions between two objects each of which is massive enough to be considered at least a planetary embryo. The putative collision suffered by the proto-Earth that created the Moon is a prime example, though most Solar System bodies bear signatures of such collisions. Current planet formation models predict that an epoch of giant impacts may be inevitable, and observations of debris around other stars are providing mounting evidence that giant impacts feature in the evolution of many planetary systems. This chapter reviews giant impacts, focussing on what we can learn about planet formation by studying debris around other stars. Giant impact debris evolves through mutual collisions and dynamical interactions with planets. General aspects of this evolution are outlined, noting the importance of the collision-point geometry. The detectability of the debris is discussed using the example of the Moon-forming impact. Such debris could be detectable around another star up to 10 Myr post-impact, but model uncertainties could reduce detectability to a few 100 yr window. Nevertheless the 3 % of young stars with debris at levels expected during terrestrial planet formation provide valuable constraints on formation models; implications for super-Earth formation are also discussed. Variability recently observed in some bright disks promises to illuminate the evolution during the earliest phases when vapour condensates may be optically thick and acutely affected by the collision-point geometry. The outer reaches of planetary systems may also exhibit signatures of giant impacts, such as the clumpy debris structures seen around some stars.