Chris Lintott’s Universe

My first AAS post was a nod to the talk I’ve just been to, a review of how astronomers meet their end by Thomas Hockney of the University of Northern Iowa. I was standing at the back having just come from another session, and so didn’t catch the names but here are the highlights:

First, the good news. Most astronomers die from natural causes. The most notable exception is probably Giovanni Bruno who was burnt at the stake. Dr Hockney noted, though, that maybe he shouldn’t be considered an astronomical martyr, having been killed for heresy not astronomy, and that he in fact deserved little sympathy having returned to Rome. As Hockney commented, any sane person should at least expect the italian inquisition.

The catalogue of slaughter included the Soviet astronomer killed in one of Stalin’s purges who unfortunately implicated the rest of his observatory staff as spies before he went, the asteroid hunter killed while one discovery away from his 100th minor planet, the great Persian astronomer Ulugh Beg who, killed by his son, goes down as the only astronomical patracide (to date) and many, many more…

Astronomy can sometimes feel like an arms race between observers and theorists. Both groups are often convinced that they’re completely right and – at least over a drink at the end of the day – take great pride in being ahead of the game. The latest battleground is in the field of extrasolar planets, and results from this lunchtime’s press conference will have cheered both sides.

Rory Barnes of the University of Arizona scored an early goal for the theorists, proudly announcing the first successful prediction of a planet since Neptune was discovered more than 160 years ago. His theory suggests that systems with multiple planets are often dynamically unstable, meaning that a small change in their orbits would lead to chaos. He also suggested that all such positions tend to have planets – solar systems tend to be ‘packed’. The system he studied, HD 74156, was already known to have two planets, and computer simulations indicated the presence of a gap. Sure enough, a couple of months ago, a planet was found in the gap just as Barnes predicted. Sara Seager, who gave an excellent talk on the field yesterday, congratulated him, and pointed out that this field littered with predictions which turn out to be wrong – but not this one.

Any theorists who were looking forward to the full time whistle should have listened to Carl Melis’ talk just a few minutes later. Looking through an old data set (from the IRAS satellite which went into orbit in 1983). His team have found two very confusing stars. They look like a type of young star called classical T Tauri stars, which have dusty disks, jets and lots of infrared light (see image above). So do the two stars Melis was studying, but there isn’t much lithium in them, which indicates that they are old. (Stars `burn’ lithium so its concentration should be highest when they’re young). So these are old stars pretending to be young, and possibly undergoing a second wave of planet formation. No-one predicted this, and I’m looking forward to seeing what the reaction might be and what explanations people will come up with.

I like the United Kingdom InfraRed Telescope (UKIRT); they do amazing work and have been doing so for 25 years. However, they’ve just released one of the most stunning data sets I’ve seen for a long time – the first release from their deep infrared survey, UKIDSS. This is the deepest and largest infrared survey ever made, the result of work that’s been going on since 2005. Sadly I missed the press conference as I was working on my talk, but luckily, Pamela has the full story here. And if you’re more a pictures than a words person, I recommend you jump straight into the site here and explore the gallery. The images are great, but my favourite UKIRT image is still the one below – the Chicken nebula.

Update Stuart reminds me that there’s an amazing Zoomable image from the part of the survey that looks along the plane of the Milky Way.