I took a series of exposure and I would like to know whether there is a way to align them such that a given star in the different images will be at the same xy coordinates. I want to do this automatically without needing to go into each image and identify the stars manually.

If your images have a reliable WCS, you can use a task like WREGISTER (or others in the IMMATCH package) to align them to a reference image. Otherwise see tasks like IMALIGN if you have some initial idea of the shifts.

I do not have WCS and the shifts seems not to be predictable. Some softwares such as Maxim DL has an auto align function. Does IRAF have something similar? I do not want to physically identify stars in each image due to the large number of images acquired.