The dynamical complexity of surface mass shedding from a top-shaped asteroid near the critical spin limit
|Author:||Yu, Yang1; Michel, Patrick2; Hirabayashi, Masatoshi3;|
1Beihang University, Beijing 100191, People's Republic of China
2University of Nice Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur, B.P. 4229, F-06304 Nice Cedex 4, France
3Department of Aerospace Engineering, Auburn University, 211 Davis Hall, AL 36849, USA
4Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
5Tsinghua University, Beijing 100084, People's Republic of China
6Department of Astronomy, University of Maryland, College Park, MD 20742, USA
7Astronomy Research Unit, University of Oulu, Oulu FI-90014, Finland
|Online Access:||PDF Full Text (PDF, 3.6 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2018080933554
|Publish Date:|| 2018-09-21
The regolith transport near the surface of an asteroid is inherently sensitive to the local topography. In this paper, conditions of surface mass shedding and the subsequent evolution of the shedding material are studied for the primary of 65803 Didymos, serving as a representative for a large group of top-shaped asteroids that rotate near their critical spin limits. We considered the influences of an asymmetric shape and a non-spherical gravity, and demonstrate that these asymmetries play a significant role in the shedding process as well as in the subsequent orbital motion. The mass shedding conditions are given as a function of the geological coordinates, and show a clear-cut dependency on the local topographic features. We find that at different stages of the Yarkovsky–O’Keefe–Radzievskii–Paddack spin-up, the bulged areas exhibit a uniform superior advantage of enabling mass shedding over the depressed areas. "Dead zones" free from mass shedding are found around the polar sites. Numerical simulations show that the orbital motion of the shedding material experiences a drastic change as the spin rate is approaching the critical limit. The "mass leaking" effect is reinforced as the spin rate increases; the lower spin rates correspond to a higher capability of trapping the lofted particles in the vicinity of the asteroid, which statistically improves the probability of collisional growth in orbit. We also find that the topological transition of the equilibrium point can in practice lead to rapid clearance of the shedding material and transport of their orbits to larger distances from the surface.
The astronomical journal
|Pages:||47 - 61|
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
115 Astronomy and space science
This work was supported in part by NASA grant NNX15AH90G awarded by the Solar System Workings program. Y.Y. acknowledges support from Natural Science Foundation of China (Grants No. 11702009 and No.11525208). P.M. and S.R.S. acknowledge support from the French government, through the Academies 2 and 3 of the UCAJEDI Investments in the Future project managed by the National Research Agency (ANR) with the reference number ANR-15-IDEX-01. The reference parameters of the Didymos system were provided by the ESA-AIM Team. The simulations were performed using the cluster Tianhe-2 located in the Chinese National Supercomputer Center (China).
© 2018. The American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.