Spinoza Prize for astrophysicist Ignas Snellen
With his clever measuring methods Ignas Snellen – together with his team – was the first to detect carbon monoxide in the atmosphere of exoplanets. For his pioneering work the Leiden astrophysicist has been awarded the Spinoza Prize, the highest academic honour in the Netherlands. The prize of 2.5 million euros will enable his research group to continue the search for a twin to Earth, a habitable planet.
Congratulations! When did you hear the news?
‘I was just taking our two dogs out for a walk when NWO phoned me. I was really surprised, flabbergasted. It’s a huge honour and perfect timing too. My European grant, the ERC Advanced Grant, ends this year and this Spinoza Prize will mean I can continue my research without having to jump through hoops applying for new grants.’
The Dutch Research Council (NWO) announced the news on 17 June. Alongside Ignas Snellen three other professors will receive the Spinoza Prize: Thea Hilhorst (Professor of Humanitarian Aid, Erasmus University Rotterdam), Klaas Landsman (Professor of Mathematical Physics, Radboud University Nijmegen) and Corné Pieterse (Professor of Plant-Microbe Interaction, Utrecht University).
How are you going to spend the prize money?
‘The money will allow me to keep our research group going. For one night of observation with the ground telescope in Chile it can easily take one researcher half a year to figure out the data. Our team relies on all the different specialisations that allow us to get so far. I also want to make more money available for our new isotope research, which can tell us more about the origins and composition of planets.’
Which research is this prize for?
‘Together with my team I developed a method to use ground telescopes to study exoplanets – planets that orbit a star other than our sun. Space telescopes are much more expensive and consequently smaller, and aren’t as good at detecting weak signals. The problem with a ground telescope, however, is that it first has to look through our own Earth’s atmosphere. We’ve developed a calibration technique that filters out this effect and allows us to distinguish the Earth’s spectrum from that of the exoplanet. We use high-resolution spectroscopy to measure the wavelength and colours of the exoplanet that tell us more about its characteristics. The presence of water vapour, for example, or the planet’s rotational speed.’
What results has this ‘Leiden’ method yielded?
‘For years we were the only research group in the world working like this, but nowadays the method is being used in lots of places. We’ve built a measuring system for the ground telescopes on La Palma and Chile and discovered several new exoplanets. Even more interesting: we were the first to detect carbon monoxide and water vapour in the atmosphere of exoplanets. We were also able to determine the rotation and weather patterns such as winds for a number of exoplanets. They are relatively close to the Earth, by the way; planets further away are still too difficult.’
‘I hope to be able to observe oxygen in my time as a researcher.’
The ultimate goal is to find a habitable twin of Earth. When might that be possible and how is your research group contributing?
‘In about five years’ time the ELT, the Extremely Large Telescope, will be ready in Chile. This telescope with a diameter of 39 metres will be a giant leap forward. Then we may soon be able to find water vapour and other gases in more places. An even bigger breakthrough would be observing oxygen because that can be an indication of a planet with life. However, that could take a while: it will probably only be possible once the ELT is working with ‘second generation’ instruments. Then I expect to be able to make spectacularly better observations. There’s a planet revolving around our neighbour Proxima Centaurus that is in such an orbit that the climate may be like the one on Earth. It will be really exciting to see what we find there.’
Could that be extraterrestrial life?
‘Who knows, but in that case I’m thinking mainly of bacterial life rather than all the forms as we know them here. Once these second-generation instruments are operational, in 2035 or maybe a bit sooner, we’ll be able to study this for a handful of planets that are close to their sun. I’m 52 now and I hope to be able to observe oxygen in my time as a researcher. Or at least to see other researchers finding it.’
Text: Linda van Putten
Photo above article: Monique Shaw