This talk by Ewine van Dishoeck, Professor of Molecular Astrophysics at Leiden University, is the third in a series of eight special mini-lectures by Academy Professors. The Academy hopes that the series will draw special attention to this exceptional group of professors and their research.
Ewine van Dishoeck
Building molecules, stars, planets between the stars
One of the most exciting developments in astronomy is the discovery of planets around stars other than our Sun. Nearly 1000 exo-planets have now been detected. But how do these planets form, and why are they so different from our own solar system? Which ingredients are available to build them? Thanks to powerful new telescopes, including the Herschel Space Observatory, astronomers are starting to address these age-old questions scientifically. In this talk, an overview will be given of how stars and planets are born in the extremely cold and tenuous clouds between the stars in the Milky Way. These clouds also contain water and a surprisingly rich variety of organic material. How and where was the water formed that is now in our oceans on Earth? Can these organic molecules end up on new planets and form the basis for pre-biotic material? The Atacama Large Millimeter/submillimeter Array (ALMA), under construction in Chile and planned to be fully operational by late 2013, will be able to zoom into the planet-forming zones of disks around young stars and revolutionize this field in the near future.
Nienke van der Marel
The growth of small dust grains to planets
Planets are formed in disks of gas and dust around young stars. The dust grains are initially only about a micrometer in size, so they need to grow more than 10 orders of magnitude to become a planet. This growth process already has problems at start: although dust grains can grow by collisions and sticking, they are just as easily destroyed or fall into the central star as soon as they have grown a little bit. The dust would need to be 'trapped' in one place in order to grow large enough. I will present early ALMA observations of a disk that show the first observational evidence for such a dust trap. With ALMA we can zoom in on the gas and dust distribution of these disks. Both are necessary to understand the dust growth and planet formation process.