--------------------------------------------- PLANET ANOMALY ALERT 2004 #9 (issued 28-Jun, 15:35 UT) --------------------------------------------- OGLE 2004-BLG-280 anomaly: Planetary caustic crossed? Dear Colleagues, after OGLE data showed a peak near HJD=2453169 (12-Jun) at only ~ 0.3 mag above baseline, the light curve showed another rise from 0.2 mag to 0.4 mag above baseline between HJD=2453178 (21-Jun) and 2453183.8 (27-Jun, 7:10 UT). PLANET has been able to collect data with the Danish 1.54m telescope at ESO LaSilla (Chile) from HJD=2453184.549 (28-Jun, 1:10 UT) to HJD=2453184.889 (28-Jun, 9:20). We are currently not sure whether we can trust our preliminary data reduction, but if we do so, the most likely nature of the observed anomaly is a caustic entry around HJD=2453184.5 followed by a caustic exit around HJD=2453184.9, i.e. only about 10 hours (!) later. The source therefore might have crossed a small caustic associated with a planetary companion to the lens, but we consider other binary lens configurations also being possible. Since the seeing varied significantly during the course of our observations, we might at all be fooled although the size of deviations is larger than typical for being caused by such effects. Despite the fact that the most interesting and useful part of this event might have been passed, a dense monitoring is recommended since it is believed that the event still shows an anomalous behaviour (which is undoubtedly present). Event: OGLE 2004-BLG-280 RA (J2000): 18:05:21.09 Dec (J2000): -28:24:14.5 The baseline I magnitude reported by the OGLE team is 16.758. For more information: PLANET: http://planet.iap.fr/currentevents.html OGLE: http://www.astrouw.edu.pl/~ftp/ogle/ogle3/ews/blg-280.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.