The asteroid 85 Io has been observed using CCD and photoelectric photometry on 18 nights during its 1995-96 and 1997 apparitions. We present the observed lightcurves, determined colour indices and modelling of the asteroid spin vector and shape. The colour indices (U-B = 0.35±0.02, B-V = 0.66±0.02, V-R = 0.34±0.02, R-I = 0.36±0.02) are as expected for a C-type asteroid. The allowed spin vector solutions have the pole co-ordinates λ0 = 285±4°, β0 = -52±9° or λ0 = 108±10°, β0 = -46±10° and λ0 = 290±10°, β0 = -16±10° with a retrograde sense of rotation and a sidereal period Psid = 0d.286463±0d.000001. During the 1995-96 apparition the International Occultation Time Association (IOTA) observed an occultation event by 85 Io. The observations and modelling presented here were analysed together with the occultation data to develop improved constraints on the size of the asteroid. The derived value of 164 km is about 5% larger than the IRAS diameter.
|Number of pages||4|
|Journal||Planetary and Space Science|
|Publication status||Published - 1999|
ASJC Scopus subject areas
- Space and Planetary Science
- Astronomy and Astrophysics