--------------------------------------------- PLANET ANOMALY ALERT 2004 #4 (issued 3-Jun, 20:45 UT) --------------------------------------------- Possible caustic passages in OGLE 2004-BLG-159 Dear Colleagues, recent PLANET data observed with the Danish 1.54m at ESO LaSilla might indicate that a fold-caustic entry started at HJD-2450000 = 3159.7 and the source only took about 3 hours to cross, while the magnification reached a peak about 2.8 mag above baseline. However, unfavourable conditions make the reduction of the data quite a difficult task and we may be fooled by some weird effects, which cause the data not to represent proper magnitude measurements. If indeed a caustic entry has been observed, the rapid fall after the caustic peak indicates that the corresponding caustic exit may occur very soon and might even already be in progress, so that a dense coverage of this event is strongly indicated. If the time between the caustic passages is only a few days, the caustic may be associated with a planet around the lens star. Since no rising part after the caustic entry has yet been observed, it is currently impossible to give a reliable estimate of the time of the caustic exit. Event: OGLE 2004-BLG-159 RA (J2000): 17:58:38.08 Dec (J2000): -30:58:46.1 The baseline I magnitude reported by the OGLE team is 13.978. More information is available from PLANET at 'http://planet.iap.fr' or from OGLE at 'http://www.astrouw.edu.pl/~ftp/ogle/ogle3/ews/2004/blg-159.html'. -------------- On behalf of the PLANET collaboration, Martin Dominik %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% If you prefer not to receive further PLANET Anomaly Alerts, please send an e-mail to planet@iap.fr.