SEARCHING FOR PRE-BREAKUP IMAGES OF THE SPLIT COMET-D SHOEMAKER-LEVY-9 FROM KISO-SCHMIDT PLATES/

We searched for images of D/Shoemaker-Levy 9 (SL9) before breakup from the 58 Kiso Schmidt plates covering; November 1986 to March 1992, whi ch were initially taken for the orbital improvements of the jovian out er satellites. The breakup of SL9 into a chain of approximate to 20 fr agments is believed to have been due to tidal forces during an extreme ly close approach to Jupiter in July 1992. We made an extensive search of moving objects near the areas predicted from the errors in the ado pted orbital elements of SL9 and detected four possible ''candidates'' of SL9 before breakup. We applied orbital determination methods for o ne object and compared motions with SL9's predictions for the other th ree objects. We could not obtain orbits which are consistent with the likely SL9 orbits. This leads us to conclude that an upper limit diame ter of prebreakup SL9 is 24-37 km, which is consistent with the diamet ers estimated by other investigators. (C) 1997 Elsevier Science Ltd. A ll rights reserved.