The crater model of an active area as applied to comet 81P/WILD-2

Both temperature and sublimation regime of an active region on the comet Wild-2 nucleus, considered as a conical hole in the dust mantle, are calculated in the present paper. All the calculations are carried out for the case, when the season effects are distinctly expressed. It is shown that the additional heating by the infrared radiation from the hot side surface of the crater results in amplification of sublimation. The temperature and amplification factors are defined for different geometrical parameters of the active region. They were calculated separately for icy bottom and dusty walls. Practically there are no changes of the temperature of the icy bottom over the whole period of rotation. It is stabilized by sublimation and income of reradiated energy from the dust walls heated by the Sun. The obtained results show that a conical crater structure on the surface of the comet Wild-2 nucleus intensifies sublimation by a factor ⩽1.8.