Can ice survive in main-belt comets? Long-term evolution models of comet 133P/Elst-Pizarro




We present detailed evolutionary calculations spanning 4.6 × 109 yr for a model representing main-belt comet 133P/Elst-Pizarro, considering different initial compositions: mixtures of ices and dust. We find that only crystalline H2O ice may survive in the interior of the nucleus, and may be found at depths ranging from ∼50 to 150 m. Other volatiles will be completely lost. We further show, by means of fully three-dimensional evolutionary calculations, that if the ice is exposed, say as a result of a collision, the resulting activity is similar to the observed pattern of the behaviour of the comet for a large spin axis inclination, even if only a patch of ice is exposed.