OGLE 2004-BLG-280 anomaly: Planetary caustic crossed?

OGLE 2004-BLG-280 anomaly: Planetary caustic crossed?

First posted on homepage: 28-Jun-2004
Moved to news archive: 5-Jul-2004

OGLE data on this event showed a peak near HJD=2453169 (12-Jun) at only ~ 0.3 mag above baseline which was followed by 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). Subsequently, 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 doubt 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. The suspected anomaly being present in our data has been reported in PLANET anomaly alert 2004 #9 (issued 28-Jun, 15:35 UT).

We provide a regularly updated lightcurve, showing PLANET and OGLE data.


back to the PLANET Homepage