On the origin of P/Halley dust component

Experimental and computational study of the radiation-induced decomposition of formaldehyde. Implications to cometary nuclei

“…According to available estimates comet Halley has made about 1000 passages near the Sun and lost in each passage an equivalent of a matter layer of about 1 m (Mukhin et aL, 1989) to 10 m (Mitchell et al, 1989). Since the surface temperature of a comet may be increased as the comet approaches the Sun, the result may be that some of the outer layer may be burned off but some radiation damage may migrate inwards as the comet leaves the Sun.…”

“…Estimates of the contribution of ionizing radiation, both internal (decay of imbedded radionuclides) and external (cosmic rays) to the absorbed dose inventory of cometary nuclei have been made by Dragani6 and coworkers (Dragani~ et al 1984(Dragani~ et al , 1987Ryan and Dragani6, 1986;Dragani6 and Dragani~, 1988). Their calculations seem to indicate that ionizing radiation may have had a more important role than is generally admitted (Mukhin et al, 1989;Mitchell et aL, 1989;.…”