No. 113/2021

HOW DO PLANETS COME FROM DUST, MS PINILLA? Stars, dust and baby planets are the orbit of astrophysicist Paola Pinilla’s research. With the help of high-performance telescopes on Earth, she regularly visits delivery rooms in the cosmos, observing protoplanetary discs of gas and dust that rotate around young stars. The gas and dust are left over after a star is born; they then collect in the discs, from which new planets are formed. The dust particles in these discs are microscopically small and com- posed of minerals. They are coupled with hydrogenous gas which enables them to move within the discs. When they collide, the parti- cles bond, collect additional dust particles, increase in size and are compacted by the collisions. Eventually, pebble-like entities known as planetesimals are formed, the precursors and building blocks of new planets. “We want to fully explain the physical conditions under which new planets are born, as well as the factors that affect their diversity,” says Paola Pinilla, outlining her research, which combines observa- tional data with model calculations. As gas is normally invisible, it is hard to observe. Pinilla therefore relies on numerical and dynamical simulations of the gas to investi- gate the conditions and physical processes inside a protoplanetary disc. The angular momentum within the disc, magnetic fields, low gravity and the speed at which the particles collide are all factors that play a role. Paola Pinilla assumes that the next five to ten years will bring rev- olutionary observations of new planets, which will also take her closer to her personal goal: to understand how dust was once the origin of our solar system, including our Earth. Text ESTHER SAMBALE Sofja Kovalevskaja Award Winner DR PAOLA PINILLA heads “The Genesis of Planets” research group at the Max Planck Institute for Astronomy in Heidelberg. 7 HUMBOLDT KOSMOS 113/2021