I'd be wary of the Hipparcos catalogue...it named quite a few stars as NSV (Newly Suspected Variables) when in fact they weren't.
I've got a paper for you here and 2 MS Word documents on the stars they looked at. Hip44599 is listed as HR3643...it's F9II and definitely variable, but very small amplitude = 0.02mag, probably why it appears as "constant".
You'll also have plenty of other stars to look at from the lists
