ENCOUNTERS OF THE SUN WITH NEARBY STARS IN THE PAST AND FUTURE

The relative space motions of the Sun and nearby stars are considered. The coordinates and velocities of the stars are taken from the Catalo gue of Nearby Stars by Gliese and Jahreiss (1991). The minimum space s eparation between the Sun and every star as well as the corresponding moment of time are calculated by two ways. Firstly, the straight line motions are considered. Secondly, the effect of the Galaxy potential i s taken into account. The Galaxy model proposed by Kutuzov and Ossipko v (1989) is used. Twenty five stars approaching the Sun closer than tw o parsecs are selected. The effects of the uncertainties in the observ ational data are studied. The influence of the encounters to the Oort cloud is discussed.