报告题目：The Strength of Rubble Pile Asteroids: Evidence and Implications (Planetary Science topic), which I plan it as a report to the university undergraduates and graduates

　　报告人：Prof. Daniel J. Scheeres

　　摘要：Rubble pile asteroids have been frequently characterized as being cohesionless, self-gravitating aggregates of boulders and grains. This picture has motivated many geophysical theories for how these bodies evolve in the solar system, and what assumptions can be made concerning their evolution and exploration. However, recent astronomical observations of asteroid 1950DA and active asteroid P/2013 R3 have provided evidence that this picture is incomplete, and indeed that rubble pile asteroids can exhibit a degree of cohesion between their components. The net effect of even small amounts of cohesion has significant implications for the evolution of small asteroids in the main belt and in the NEA population, and will be reviewed. A recent theory by Sanchez and Scheeres provides one hypothesis for how such cohesive strength could exist in gravitationally attracting aggregates — through weak van der Waals attractive forces between the finest grains in a rubble pile. This theory has several additional implications for the asteroid environment that have specific predictions that can be probed with both ground-based observations and with spacecraft rendezvous missions such as Hayabusa II and OSIRIS-REx.

　　时间：7月7日（周五）上午10点

　　地点：仙II 311

欢迎各位老师、同学参加！

　　 南京大学天文与空间科学学院