Eclipsing Binary Stars

Today we are looking at eclipsing binary stars which are stars which orbit so close around each other that they appear to be a single star when we observe them from Earth.


Eclipsing Binary Star (Click to Enlarge)

I have put together a picture to try and show what the eclipsing binary star would look like. You can see the primary star in front and the closely orbiting secondary star on the right just beginning to disappear behind the primary star.


If you looked at these eclipsing binary stars as they appear in the picture at the moment, you will be seeing the light from both stars so they will of course appear brighter in the night sky.

However, after the secondary star has been eclipsed after it moves behind the binary star, then we no longer see the light coming from the secondary star. Therefore the only light you see is from the primary star and you then get a drop in magnitude. When the secondary star begins to re-emerge on the other side of the primary star, then you would see the brightness of the eclipsing binary stars begin to increase.

From Sydney we are fortunate enough to be able to see an eclipsing binary star and this was mentioned in one of our postings in Sydney Universe Watch which mentions where it is and how to find it. To find out  where to see this eclipsing binary star, click on the following link and read the posting for November 17.

Sydney Universe Watch should be completely up to date with the objects that can be viewed in the month of November.  On Sunday we will be looking at the last of the November objects and start looking at the objects best viewed in December from next Tuesday.


~ by sydneystargazers on November 25, 2009.

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