EDP Sciences
Free access
Volume 371, Number 2, May IV 2001
Page(s) 748 - 752
Section The solar system
DOI http://dx.doi.org/10.1051/0004-6361:20010372

A&A 371, 748-752 (2001)
DOI: 10.1051/0004-6361:20010372

CCD photometry, spin and shape model of the asteroid 1572 Posnania

T. Michalowski1, W. Pych2, T. Kwiatkowski1, A. Kryszczynska1, P. Pravec3, W. Borczyk1, A. Erikson4, W. Wisniewski5, F. Colas6 and J. Berthier6

1  Astronomical Observatory, A. Mickiewicz University, Sloneczna 36, 60-286 Poznan, Poland
2  Copernicus Astronomical Center, Bartycka 18, 00-716 Warszawa, Poland
3  Astronomy Institute of the Academy of Sciences, Ondrejov, Czech Republic
4  Institute of Space Sensor Technology and Planetary Exploration, Rutherford str. 2, 12489 Berlin, Germany
5  Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721, USA
6  Institut de Mecanique Celeste, 77 Av. Denfert Rochereau, 75014 Paris, France

(Received 19 January 2001 / Accepted 17 March 2001)

Lightcurves of the asteroid 1572 Posnania were obtained at six observatories on 19 nights during four apparitions: in 1993, 1994-95, 1996, and 1999. The synodical period is found to be 8.048 hours and the observed amplitudes of brightness variations are in the range of 0.37-0.40 mag. The sense of rotation is retrograde with a sidereal period $P_{\rm
sid} = 0.3353931 \pm 0.0000003$ days. The ecliptic coordinates of the pole of this asteroid are $\lambda_{\mathrm p} = 46^{\circ} \pm 6^{\circ}$ and $\beta_{\mathrm p} = -65^{\circ} \pm 5^{\circ}$. The shape of Posnania can be approximated by a triaxial ellipsoid model with semiaxes ratios $a/b = 1.35 \pm 0.01$ and $b/c = 1.04 \pm 0.03$.

Key words: techniques: photometric -- minor planets: asteroids

Offprint request: T. Michalowski, tmich@amu.edu.pl

© ESO 2001