At first glance I thought it looked German (I take German) but I didn't recognize it as coming from any sort of root and a I looked it up on dict.cc which is the site I use most as a dictionary. It doesn't have anything. After doing a quick google, I found a family's website that mentioned something about Stahrs in Denmark. So I looked it up on a Danish dictionary site (you'd think that if it were Danish it would have a similar German equivalent which doesn't seem to exist) and I couldn't fine anything. I'm sure you've already found that website too. Sorry I couldn't be of more use!
Peace