Asteroid 83 Beatrix - photometry and model.

Asteroid 83 Beatrix was observed on 30 nights during five oppositions: 1984 (Lowell Observatory, Arizona), 1986, 1988, 1990, and 1991 (Kharkiv, Ukraine). A new value of the synodical period was found to be 10.108 hours . The phase curves at the 1984 and 1988 apparitions (H=8.69, G=0.20) seem to differ from those resulting from 1986 and 1990 observations (H=8.58, G=0.15). The difference may be caused by the changing aspect of the asteroid. Using all available lightcurves we have found that Beatrix is a retrograde rotator with a sidereal period of 0.4213796+/-0.0000005days and the ecliptic coordinates (B1950.0) of its north pole are (3deg,-37deg) or - according to the second solution - (172deg,-31deg). An asteroid shape has been approximated by a triaxial ellipsoid with the semiaxis ratios a/b=1.26, b/c=1.16.