Planet Formation Around HL Tau

Phil Plait, of Bad Astronomy fame, has written an article about probable planet formation around the young star HL Tau. Link. As can be seen from the picture, there are several gaps in the protoplanetary disk, indicating that planet formation has already begun in earnest. Plait guesses there are at least 3 planets, although some in the corners of the internet that I hang out in suspect that some of the gaps could be due to resonances (in a manner similar to the Kirkwood gaps), and there are actually fewer planets.

In any case, while there have been numerous pictures of dust disks around young stars before (Beta Pictoris is one of the earliest I can remember), this is one of the best ones that I can remember. Pretty fortunate that it was oriented roughly face-on toward Earth.