The Laboratory Astrophysics Prize, LAD’s highest honor, is given to an individual who has made significant contributions to laboratory astrophysics over an extended period of time. For decades Wiescher has pioneered experimental techniques to reproduce conditions that drive explosive nucleosynthesis in novae and X-ray bursters, significantly advancing our understanding of the evolution of accreting white dwarfs and neutron stars, respectively. He combines pathbreaking laboratory techniques with insightful theoretical modeling to study nuclei produced in a variety of astrophysical scenarios. For example, he demonstrated the need for radioactive ion beams to investigate explosive nucleosynthesis and developed a deep underground accelerator laboratory to study nuclear reactions in quiescent stellar burning like that going on deep inside our own Sun.
The most powerful star explosions are , which are bright enough to briefly outshine their entire galaxies. The mind-boggling heat and force of these outbursts help forge the heavier elements, a process known as explosive nucleosynthesis.
Abstract: The extreme luminosity and their fairly unique temporal behaviour have made supernovae a superb tool to measure distances in the universe. As complex astrophysical events they provide interesting insights into explosion physics, explosive nucleosynthesis, hydrodynamics of the explosion and radiation transport. They are an end product of stellar evolution and provide clues to the stellar composition. Since they can be observed at large distances they have become critical probes to further explore astrophysical effects, like dust properties in external galaxies and the star formation history of galaxies.
Image (click to enlarge): The upper left panel is a composite made up of three infrared views shown in the remaining panels. The bottom left view shows argon gas (green) that was synthesized as it was ejected from the star. The bottom right view shows a collection of dust (red), including proto-silicates, silicate dioxide and iron oxide. The fact that these two features line up (as seen in yellow in the combined view) tells astronomers that the dust, together with the gas, was created in the explosion. The upper right panel shows silicon gas (blue) deep in the interior of the remnant. This cooler gas, called the unshocked ejecta, was also synthesized in the supernova blast. Credit: NASA/JPL-Caltech.
Cassopeia A is a supernova remnant some 11,000 light years away. Turning the attention of the Spitzer Space Telescope on this object allows us to examine the different elements within it, a useful exercise because it helps to answer a question about the early universe: Where did the interstellar dust so essential for the formation of stars and planets — not to mention the creatures that live on planets like ours — come from?