Asymmetric outgassing of short-periodic comets with respect to perihelion

The asymmetric model accounting for nongravitational effects is applied to improve orbits of a number of short-periodic comets that have shifts of maximum brightness with respect to their perihelions. Shifts of maximum gas productivity have been obtained for 20 short-periodic comets using photometric and dynamic methods. When using the photometric method, the maximum gas productivity is supposed to coincide with the maximum brightness of the comet, while, in the dynamic approach, it is believed to correspond to the maximum nongravitational acceleration. An analysis and evaluation of the results have been carried out.