Shaping the Kuiper belt size spectrum
Margaret Pan (Caltech) - 7 Nov at 12:00 noon
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) indicates that the size spectrum 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 rubble piles with low material strength rather than solid
monoliths. This gives a power-law slope q=~3 where the number N(>r) of
KBOs larger than a size r scales as r^(1-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). The agreement with observations indicates
that KBOs are effectively strengthless rubble piles.
The seminar will be held in 544 Campbell Hall.
Return to seminar schedule