Pluto's structure and composition suggest origin in the solar, not a planetary, nebula

by: Mckinnon, W. B.; Mueller, S.

ABSTRACT

The four explanations for Pluto's large rock ice ratio, (1) formation in
the inner solar system, (2) volatile loss during accretion, (3) volatile
loss during the large-body impact that created Charon, and (4) formation
as a large, ice-poor outer solar system planetesimal, are considered. It
is shown that only the last two explanations are feasible, and that the
depletion of water ice in Pluto is so severe that both explanations may
be necessary.

Nature, ISSN 0028-0836, vol. 335, Sept. 15, 1988, p. 240-243.