The interiors of Pluto and Charon - Structure, composition, and
implications

by: Simonelli, D. P.; Reynolds, R. T.

ABSTRACT

Recent models of the internal structure of Pluto and Charon, made possible
by analysis of the Pluto Charon mutual events are reviewed. At a mean densi-
ty of just over 2 g cu cm and a predicted rock mass fraction of roughly
0.7, the Pluto Charon system is significantly rockier than the icy satel-
lites of the giant planets, a contrast which may reflect its formation in
a CO-rich outer solar nebula rather than a circumplanetary nebula. Pluto
and Charon may in fact be so rocky that they lost volatiles early in their
history (possibly during a Charon-forming impact event), although this is
still an open issue.

Geophysical Research Letters (ISSN 0094-8276), vol. 16, Nov. 1989, p. 1209-
1212.