J. Herzog (Astronomical Institute), T. Schildknecht (Astronomical Institute)
Keywords: SSA
Abstract:
The internal catalogue of space debris objects maintained by the Astronomical Institute of the University of Bern (AIUB), contains many objects with observations over long time spans. They are observed regularly with ESA’s 1-meter telescopes in Tenerife (Spain), AIUB’s 1-meter telescope ZIMLAT and 30-centimeter telescope ZimSMART in Zimmerwald near Bern (Switzerland).
We analysed Area-to-Mass ratio (AMR) variations of 10 objects for which observations covering a time span of one year or more were available. The mean AMR values ranges from 0.02 square meter per kilogram to 30 square meter per kilogram. The class of Low Area-to-Mass ratio objects (LAMR) with AMR values lower than 1 square meter per kilogram is covered as well as the class of High Area-to-Mass ratio objects (HAMR).
Although the observations were post-processed, the same approach as in the routine processing was used: observation arcs as long as possible are fit with a constant AMR value. As a consequence, the AMR values are averaged over these intervals. Also, the individual arc lengths are varying and intervals are overlapping, because observations used in previous orbit determinations are used again. If adding results in poor fits, the oldest observations are taken off until the requirements for a “good orbit’ are fulfilled. The procedure acts as a low-pass filter and only AMR value variations with low frequencies may be determined.
For this small sample, the LAMR objects do not show any significant AMR value variation, the mean AMR values are constant within the estimated uncertainties. In contrast, some of the HAMR objects show significant variations of the AMR values.
Date of Conference: September 11-14, 2012
Track: Poster