Abstract
The observed size distribution of Kuiper belt objects (KBOs) - small icy and rocky Solar System bodies orbiting beyond Neptune - is well described by a power law at large KBO sizes. However, recent work by Bernstein et al. (2004, Astron. J. 128, 1364-1390) indicates that the size distribution breaks and becomes shallower for KBOs smaller than about 70 km in size. Here we show that we expect such a break at KBO radius ∼ 40 km since destructive collisions are frequent for smaller KBOs. Specifically, we assume that KBOs are gravity-dominated bodies with negligible material strength. This gives a power-law slope q ≃ 3 where the number N>r of KBOs larger than a size r is given by N>r ∝ r1-q; the break location follows from this slope through a self-consistent calculation. The existence of this break, the break's location, and the power-law slope we expect below the break are consistent with the findings of Bernstein et al. (2004, Astron. J. 128, 1364-1390). The agreement with observations indicates that KBOs as small as ∼ 40 km are effectively strengthless.
Original language | English |
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Pages (from-to) | 342-348 |
Number of pages | 7 |
Journal | Icarus |
Volume | 173 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2005 |
Externally published | Yes |
Bibliographical note
Funding Information:We thank Oded Aharonson and Andrew MacFadyen for useful discussions. M.P. is supported by an NSF graduate research fellowship.
Keywords
- Impact processes
- Kuiper belt objects