Researching the Birth of Our Solar System

After successful evaluation by an international team of experts, the Priority Programme (SPP 1385) “The First Ten Million Years of the Solar System”, coordinated at Heidelberg University, has entered its third and last two-year funding period with 29 projects slated for completion. The DFG is providing approx. 4.8 million euros to continue the research work, of which 1.2 million euros have been allocated for nine projects in Heidelberg. In SPP 1385, scientists from various disciplines are analysing extraterrestrial material to draw conclusions on how planets formed 4.5 billion years ago. Of primary interest are the small planets, or planetesimals, as pointers to the beginning of life as we know it. Prof. Dr. Mario Trieloff of Heidelberg University and Prof. Dr. Klaus Mezger of the University of Bern (Switzerland) are the coordinators of the programme established in 2010.

“At its core, the planetary formation process still remains cloaked in mystery”, stresses Mario Trieloff. According to the Heidelberg geoscientist, some questions remain largely unanswered, such as how the Earth formed from a number of smaller protoplanets and where the water on Earth originated. Extraterrestrial material from small bodies is crucial to the investigations of SPP 1385. Asteroids and comets did not evolve into large planets, but remained stuck at the small-planet stage of development. The relics of dust and rock they hold on the way to becoming larger planetary bodies have been preserved relatively unaltered. Prof. Trieloff reports that a number of significant specific questions were answered successfully in the first two funding periods. For example, scientists studied the speed at which asteroid-sized bodies formed, how long they were magmatically active, and over what period of time they held liquid water. Now the researchers will turn their attention to integrating the details of formation and development of planetesimals and larger planets into comprehensive models.

The programme is coordinated from the Institute of Earth Sciences at Heidelberg University, which is also home to projects focused on determining the age of primitive extraterrestrial material. In those studies, a new ion probe will be used to measure isotopes. The probe, expected to arrive in Heidelberg in July, is one of the few of this design worldwide, according to Prof. Trieloff. The Institute for Theoretical Astrophysics will undertake modelling, addressing the formation of the first millimetre-sized solids in the solar system, the development of early asteroids and the role of frozen water in planetary formation. The Kirchhoff Institute for Physics will conduct laboratory experiments to determine the infrared properties of silicate condensates with a view toward uncovering the details of infrared emissions of protoplanetary dust disks. The Max Planck Institute for Astronomy will build theoretical models to investigate, among other things, a new “mechanism” of planetary formation. The research projects of the entire programme are spread out over 24 locations in Germany as well as at the Institute of Geological Sciences at the University of Bern.