I would be failing in my duty as a PhD student if I didn’t post this…
I came across this link (courtesy of Derren Brown’s blog) which documents the year’s most amazing scientific images. It’s an amazing collection, so you should be more than happy to look at the first 39 images in the gallery (ranging from the effect of the Chernobyl disaster to the test firing of NASA’s Ares rocket, with volcano light shows, homemade helicopters and everything in between). If you get to image 40, you’ll see my supervisor‘s handiwork regarding the HL Tau star system.
HL Tau is a young star, with a disc of gas and dust surrounding it. When they studied this star system at radio wavelengths (using the Very Large Array in New Mexico), they found a lump of emission near the star, which appears to be a giant planet in its earliest stages of formation. My supervisor ran some simulations of the star system, which showed that the gas disc could become unstable under its own gravity, and collapse into fragments (the image is taken from that simulation). This is known as the disc instability model of planet formation, and if you have a massive disc that extends to a large radius, then making gas giants is a quick and efficient process. The if is important here – exactly how massive and large discs are in reality suggest that disc instability is probably not the primary planet formation route. In fact, it may be very unlikely.
The fact that HL Tau appears to be an example of disc instability in action makes it an important discovery. And the group isn’t stopping there. We’re still looking at HL Tau (and I’ll be pitching in too!). If we’re lucky, in the future we might even be able to see the spiral arms of the disc, and help confirm our hypotheses. Wish us luck!