maybe i should just shut up but...

At least I read it :-) I think it's a good astrophysics exercise to look at possible reasons of dimming, and then dismiss them one by one. Now, to periodically dim a star to half it's brightness and then back again, that star would have to do a really strange yo-yo movement, and at a speed that is defying known laws of physics. Anyway, while it's difficult to get exact distance measurements, we can tell the velocity of a star relative to an observer on Earth pretty reliably by examining the Doppler effect evident in it's spectrum. So there is absolutely no way that a variation in distance can have any significant impact on the brightness of eps Aur.

Ameen, we seem to be hitting the ground running! I think it's great that so many have responded to the call. I have yet to wrap my brain around the charts and what they mean. So far I have discovered that the brightening may very well be due to one of the following: gravitational lensing microlensing refracted electromagnetic radiation Gravitational lensing and microlensing I think can be ruled out as they require distances of lightyears. The Eps Auri eclipsing object is well within 1 lightyear. However, refracted electromagnetic radiation is not ruled out yet. I think this is the best candidate so far to explain the brightening. Remember that whenever light passes from one medium to another it gets refracted (more info in next paragraph). The brightening effect is not unique I hear. There are a number of other eclipsing binaries that behave in a similar manner. I think that by examining these others closely we can gain a better understanding of what is at play with Eps Auri. Last I heard the eclipsing object is roughly 10 times bigger in appearence than the primary, but has the same mass. This tells me that it is a cloud of dust that the light is being refracted through, causing the brightness. The spectrum is a "single line" spectrum, which suggests that there is only one star here. However there is other evidence (that I am trying to understand) that suggests a smaller binary pair that is orbiting the primary. I doubt that this detail rules out refracted EM radiation, though. If I am way off base one of the experts will correct me. But I feel this is close.

Hey, Ameen. While it is true (according to most of the current evidence) that the Universe is expanding, there are a couple of reasons why this can't be the cause of the eclipse. First, the rate of expansion isn't enough to justify the dimming we see. The inverse square law can be used to determine how much light you should get at a set distance. Remember epsilonAurigae loses about half its brightness during eclipse. If you do the math (basic algebra 101), you'd see that the distance to epsilon Aurigae would need to increase by ~40% to cause a 50% drop in brightness. Our favorite star is about 2000 light years away, so that would equate to a huge distance shift of around 800ly during the time of the eclipse - about 1.5 years. Needless to say, you'd be breaking the speed of light to do that. :) So not possible outside of the inflationary epoch of the BigBang, or the invention of a solar system sized warp drive. Secondly, remember the eclipse is only temporary. So that would mean that the distance would have to return to its present value and there aren't any cosmology or astrophysical models that could explain that. Keep the ideas coming! Aaron

Hi Richard I replied to the content of your post in the Thread: Forums / The Science / Data Analysis / Eclipsing Binary simulator http://www.citizensky.org/forum/eclipsing-binary-simulator asmost points in your reply originate from there. CS Wolfgang