Data collected by PLANET, OGLE, and MicroFUN showed a rise in magnification by 2.85 mag above baseline until 9-Jun, 8:10 UT. These data indicated a peak to occur on 10-Jun, 6:35 UT (-30 min/+20 min), at a rather uncertain, but in any case large, magnification of 80 (-30,+70). Events of this type harbour a exceptional potential for the discovery of extra-solar planets as well as for the study of stellar atmospheres and might provide an opportunity for measuring the mass of the lens star. More information has been given in PLANET anomaly alert 2004 #5 (issued 9-Jun, 20:50 UT).

The observation of finite source effects has been reported in PLANET anomaly update 2004 #5-1 (issued 10-Jun, 4:10 UT). These are apparent in PLANET data from the SAAO 1.0m at Sutherland (South Africa) after 9-Jun, 18:50 UT and subsequent data from the Danish 1.54m at ESO LaSilla (Chile) as well as in OGLE data. As reported in PLANET anomaly update 2004 #5-2 (issued 10-Jun, 12:45 UT), the first half of the source star passed the caustic created by the lens in about 16 hours and a peak has been observed on 10-Jun around 7:40 UT at 4.35 mag above baseline, i.e. at a magnification of ∼ 55. Continuing dense coverage will allow a measurement of limb darkening of the source star. A reliable measurement of the passage time and an assessment of parallax can moreover be used to determine the mass of the lens star.

PLANET anomaly update 2004 #5-3 (issued 10-Jun, 21:40 UT) reports that PLANET data collected at the SAAO 1.0m at Sutherland (South Africa) reveal a sign change in curvature on Jun-10 at around 21:00 UT, roughly corresponding to the source exiting the caustic created by the lens star. Together with previously collected data, we find that the caustic transit of the source lasted about 26 hours.

For the current status, have the look at the regularly updated lightcurve showing PLANET, OGLE, and MicroFUN data.