The name of the rock group is Jaaaar, and it is not a mistake: all of the a letters have their function. From what I know and I have read it means the edge of the ice, the edge where the ice ends. So hopefully this is what it means. I do not speak Estonian, but this is a very nice group and I know a few words that are of interest to me in that language.
Hihi, that's right, all the ä's fooled me. It's definetly 'edge of the ice', jää is ice and äär is edge. Would be jään ääri in my native Finnish, two words, so I didn't even think of the possibility of an word with four ä. But there you have it, so sorry about the aries Also note that the dots on the letters make a huge difference as well, a is a different letter from ä in both Estonian and Finnish, Jaaaar would be an altogether different story - the rock group is not familiar to me at all, so no comments on which one is the name (though of course I understand you simply might not be able to dot you ä:s on your keyboard).