Stars orbit the center of our Galaxy. This movement of stars leads to motion of stars relative to each other. In this portion of the lab we will examine the motion of the nearby star, Barnard's Star. This star is, in fact, the star at the center of field number 5 in the first table you used earlier. Using the Virtual Observatory, obtain an image taken through the blue filter and then one taken through the red filter. These observations correspond to different times. The blue image was taken on 13/05/1988 and the red image was recorded on 17/06/1991. Be sure to choose the GIF format for these images because this format will allow you compare the images side by side. Look for a prominent star that seems to have shifted between the two times. The shifting is relative to all the other stars in the field. Use a field of view of 7 arcminutes when making your observations!.

The GIF images that you are displaying can be printed on their own by right clicking on the images and choosing the "print" option from the menu that pops up. When you are done printing the images you can close them by choosing "quit" from the same menu.

Use the equations from the "Evidence of Stellar Evolution" page to figure out how much Barnard's Star has moved. Estimate this motion in arcseconds per year and then in parsecs per year.  Remember,

 

Actual Size = Angular Size x Distance

 

In this case it means, distance moved = angle moved times distance to the object.



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