Comet P/2010 H2 is a really interesting object discovered on April 16.
At discovery it appeared as a starlike object of mag 12-13, and no cometary appearance could be percieved, even in large telescopes. However, the chance of new asteroid of that brightness having gone previously undiscovered was virtually nill. Furthermore the previous day images were uncovered showing the field down to mag 21, with no object apparent in the predicted position! Therefore a cometary outburst was suspected and in recent hours the object has started to show a slightly non-stellar aspect. It looks very much like a Comet Holmes outburst but on a smaller scale.
Positions are provided at this link:
http://www.minorplanetcenter.org/mpec/K10/K10H12.html
Terry