--------------------------------------------- PLANET ANOMALY ALERT 2004 #5 (issued 9-Jun, 20:50 UT) --------------------------------------------- OGLE 2004-BLG-254: High-magnification peak expected Dear Colleagues, since the event OGLE 2004-BLG-254 was announced by the OGLE collaboration, it has been monitored by several teams, where data shows a brightening by 2.85 mag above baseline until 9-Jun, 8:10 UT. Based on most recently available data from OGLE and MicroFUN as well as PLANET data from the SAAO 1.0m at Sutherland (South Africa) and the Danish 1.54m at ESO LaSilla (Chile), a peak is expected on 10-Jun, 6:35 UT -30 min +20 min, at a rather uncertain magnification of 80 -30 +70, which is however unusally large in any case. The probability for planets around the lens star to show an observable signal is strongly increased for events that exhibit a large peak magnification, making them ideal targets for the detection of extra-solar planets, which alternatively yield the strongest limits on the planetary abundance if such a signal is absent. Moreover, events like OGLE 2004-BLG-254 also contain a large potential for resolving the surface brightness of the lensed source star, while the proper motion between lens and source is measured at the same time. Together with an assessment of parallax, this can result in a determination of the mass of the lens star. In order to make the optimal use of what OGLE 2004-BLG-254 can offer, dense monitoring is strongly recommended. Event: OGLE 2004-BLG-254 RA (J2000): 17:56:36.20 Dec (J2000): -32:33:01.8 The baseline I magnitude reported by the OGLE team is 16.330. For more information, you may consult: PLANET: http://planet.iap.fr OGLE: http://www.astrouw.edu.pl/~ftp/ogle/ogle3/ews/2004/blg-159.html MicroFUN: http://www.astronomy.ohio-state.edu/~microfun/Data/OB04254/ -------------- 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.