Searching for the short timescale variations in the lightcurve of minor planet 1689 Floris-Jan in 1999 and 2002

Abstract

CCD imaging photometric observations were carried out with Cousins filters in 1999 (I filter) and 2002 (R filter) on eight nights in order to search for the intrinsic short-period oscillations in the lightcurve of the slowly rotating minor planet 1689 Floris-Jan. The principal objective of the observations is to perform independent verification or rejection of the short-period oscillations in the lightcurve reported by Pych ([CITE], A&A, 343, L75). Observations made in 1999 and 2002 (this work) do not show any short-period sine-like oscillation. The observations were taken at relatively large airmass conditions and the atmospheric effects introduced large point to point scatter in some data sets in 1999 and 2002. Further observations and a detailed frequency (period) analysis of the short timescale lightcurve variations of this asteroid are strongly encouraged during the next oppositions: the next one will be in March 2005.