Stellar Citizen Science

Historical eclipse measurements of epsilon Aurigae

Over at Professor Astronomy, Kurtis recently talked about an excellent citizen science project to light on the nature of mysterious variable star epsilon Aurigae. For almost 200 years, this run-of-the-mill star has been seen to dim periodically. This is not particularly remarkable in se – many stars dim at regular intervals, typically every few days, due to a companion star or planet passing in front of it. But in the case of epsilon Aurigae, the dip in its lightcurve occurs every 27 years and lasts several hundred days – around 2 years! The eclipse lightcurve (above) also shows that the dip contains quite a few bumps. So whatever movement is causing the eclipse is very very slow, and some interaction between the two bodies appears to be going on. 

Some theories have been put forward as to the nature of the eps Aur system, such as the eclipse being caused by a disk that is slowly changing over time, perhaps due to a planet forming inside it.

Excitingly, eps Aur’s next eclipse is due to start in early August 2009 (during the International Year of Astronomy – nice timing!), and a number of institutes in the US have pulled together to organise a citizen science observing campaign of the star, called Citizen Sky, to get as much data from as many different sources as possible of the star’s upcoming eclipse. A workshop will be held at the Adler Planetarium in Chicago in August to help observers plan and carry out the observations, keep track of the data and understand the results. An online “10 star training” tutorial is also available on their lovely-looking website.

So if you have a telescope in your backyard and eps Aur will be visible from your part of the world this autumn, sign up with Citizen Sky and help fiure out what makes this star go dark.

Citizen Sky is organised by the American Association of Variable Star Observers (AAVSO), the Adler Planetarium, the California Academy of Sciences, Johns Hopkins University and the University of Denver. Prof. Robert Stencel at the University of Denver has some more info on the star and the 2009 eclipse here.