Tidal dissipation in rubble-pile asteroids

Francis Nimmo, Isamu Matsuyama

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


We develop a simple scaling argument for frictional dissipation in rubble-pile asteroids, parameterized as an effective dissipation factor Q. This scaling is combined with a prediction (Goldreich, P., Sari, R., 2009. Tidal evolution of rubble piles. Astrophys. J. 691, 54–60) for the tidal response amplitude, parameterized by the Love number k2. We compare the combined scaling with k2/Q values inferred from asteroid binaries in which the semi-major axis is determined by a balance between tidal dissipation and the binary YORP (or BYORP) effect (Jacobson, S.A., Scheeres, D.J., 2011. Long-term stable equilibria for synchronous binary asteroids. Astrophys. J. Lett. 736, L19). The k2/Q scaling matches the inferred values if dissipation is confined to a regolith layer of thickness ∼ 30 m, similar to the available asteroid regolith thickness estimates. The scaling suggests a regolith thickness that is independent of (or decreases slightly with) increasing asteroid radius; this result is consistent with at least one model of regolith generation via impacts.

Original languageEnglish (US)
Pages (from-to)715-721
Number of pages7
StatePublished - Mar 15 2019

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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