Do scientists now know what struck the surface of Jupiter on July 19, 2009?

This article: a href="http://arxiv.org/pdf/1005.2312v1" rel="nofollow"http://arxiv.org/pdf/1005.2312v1/a concludes that the impactor was most probably an icy body with a size of 0.5-1 km, that is to say, a comet.