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Hi Sebastian, It's by no means certain what's causing the differences in event timings in different wavebands, though possibly (probably?) these different events represent emission from different physical locations. The X-ray emission is probably produced in a bow shock around a companion star (at least this is one working hypothesis, though there are others), and if so its variations are dominated by 1) increases in the density in the shock as the companion plows into denser regions of eta car's wind and 2) the occultation of the shock by the wind from eta car, which absorbs X-rays and causes the sudden rapid decline in X-ray emission (though it's not clear what is causing the rather rapid "flaring" activity we seem to be seeing now). The X-ray minimum is reached when the companion moves behind eta. The IR lightcurve may be influenced by the formation of dust somewhere in the bow shock in very dense regions. This would be similar to events seen in WR+O binaries like WR 140 and WR 104. It's interesting to think that extremely hot regions which produce X-rays and extremely cold regions where dust can form can co-exist, but apparently they do. The visible light should be dominated by the photospheric emission from Eta along with scattered light off the homunculus. Presumably the variations observers like you, Chris Sterken, Arnout van Genderen and others have been seeing in the optical are produced by changes in the stellar photosphere and/or the circumstellar material, though I have to admit I'm pretty puzzled by them, though Chris and Arnout have discussed some of the changes in terms of a disk around one of the stars. Hopefully these new observations we're getting from ground and space will help confirm (or deny!) these ideas and let us pinpoint the mechanism more clearly. cheers Mike At 8:56 PM -0300 6/12/03, Sebastian Otero wrote: > > surprise! a 2.4 cts/s increase > >I have updated the visual lightcurve at: >http://ar.geocities.com/varsao/Curva_Eta_Carinae.htm >It's still on the slow rise around 5.0-5.1. >Looking at the historical data, the eclipse is more apparent in the infrared >bands than in the visual. >It happens well after the X-ray minimum has been reached. >July 11, 2003 is the predicted date according to the IR data. >Might it be possible that the visual eclipse arrives even a little later? >Why is the reason for these diferences accoring to passbands? > >A good chance for professionals to help humble amateurs understand! > >Cheers, >Sebastian. > >PS: I think the visual eclipse will be 0.1-0.15 mag. deep. I hope clouds >don't interfere in the couple of months to come. -- *********************************************************** Dr. Michael F. Corcoran Universities Space Research Association Goddard Space Flight Center Greenbelt, MD 20771 301-286-5576 (office) 301-286-1684 (fax) corcoran@barnegat.gsfc.nasa.gov http://lheawww.gsfc.nasa.gov/users/corcoran/bio.html ***********************************************************
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