‘Missing stardust problem’ solved
Dr Amanda Karakas, NCI user and Senior Lecturer in the School of Physics and Astronomy at Monash University, is moving our understanding of stardust and star formation forward thanks to updated theoretical models run on the NCI’s supercomputer.
Dr Karakas and her co-authors used theoretical models of stars to identify an important source of stardust found on Earth. They now confidently believe that one type of oxygen-rich dust originated exclusively from intermediate mass stars, which are around 4 times the mass of our Sun. This solves the so-called “missing dust problem”, which hypothesized that such stars should make copious amounts of dust but no record had been found up until now. The research team have managed to assign an origin to stardust we previously did not fully understand. The research was published in Nature earlier this year.
Bringing these findings together required a collaborative effort between nuclear physicists, geochemists and theoretical astronomers. The nuclear physicists provided a more precise understanding of the expected products of thermonuclear reaction rates that occur inside stars; the theoreticians then ran their theoretical models at NCI with the most accurate input data, and their results were compared with those of the geochemists analysing the meteorites for stardust.
Using measurements of the dust inside a particular, very old meteorite, the researchers found that its composition matched up well with their new model of what the intermediate mass stars should be producing. Dr Karakas says, “Our thermonuclear models now match the composition of the dust, because of a revision in the stars’ thermonuclear reaction rates.”
Although solving the missing dust problem is a big step forward in understanding the origin of stardust, she says, “Now we want to verify whether the amount of dust the stars are putting out into the interstellar medium matches what we have in the meteoritic record.”
Most people in the field of stellar physics use observational methods to do their research, but Dr Karakas is one of several theoreticians using computer models as well. She says that this study’s collaboration between the theoretical and experimental physicists makes it unique.