August 20, 2019

08.04.10-Epsilon Aurigae Update.

   We couldn’t resist shooting this one out there today, as it contains some fairly mind-blowing imagery. Late last year, we put a shout-out to observe the eclipsing binary star Epsilon Aurigae, a bright naked eye star that undergoes periodic diming once every 27 years. For over 190 years, this star has stubbornly not only refused to match stellar evolutionary models, but sometimes threatened to overthrow them, to boot. Now, scientists have solved the case of the disappearing star, and it’s a strange one, indeed. The variation in brightness appears to be the result of three factors; a bright type F supergiant, orbited by a hot type B star about 1,000 times dimmer shrouded in a massive dust disk. The entire system passes along our line of sight and obscures the host for an 18 month period. The grouping is about 2,000 light years distant. In fact, if Epsilon Aurigae were tipped away even 10 degrees more from our line of sight, we wouldn’t see anything unusual at all! This model of the systems’ total luminous output matches the observed brightness curve from the recent dimming. (see above)

The time lapse video above actually shows the dust disk surrounding the type B star occulting the primary. This amazing feat of resolution was accomplished by the Center for High-Resolution Astronomy array (CHARA) atop Mt. Wilson. This consists of six 1-meter scopes working in unison to have the resolving power of one enormous 1,100 foot mirror. To give you some idea of the scale, the shadow disk imaged is about a billion miles wide and about a fifth of that in thickness… this would fit nicely within the orbit of Jupiter in our own solar system…

And kudos to all those Citizen Sky watchers out there who continue to contribute to monitoring this bizarre system; as you can see, all that data collected over long cold winter nights does count!

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