Sulfur is one of the most abundant elements in the universe. If you peer into a diffuse interstellar cloud, you find loads of it—about the amount expected based on fusion patterns in the stars it was born in. However, if you look at a dense, cold molecular cloud—the kind where those stars actually form—it seems like 99% of the sulfur expected to be there is missing. Scientists have puzzled over this “missing sulfur problem” for decades, though a leading theory is that the element hides in icy dust grains, making it hard to detect.
A new paper published in Astronomy & Astrophysics from the Max Planck Institute for Extraterrestrial Physics and the Centro de Astrobiologia describes a new computer simulation model aimed at supporting the interpretation of laboratory results and testing our current understanding of sulfur evolution in interstellar ices.
The simulation was written in pyRate—a Python-based application that calculates how chemicals interact, especially between ice and gas phases. The paper marks the first successful model of the chemistry of a multicomponent interstellar ice analog with a rate-equation simulation. Scientists love “firsts,” but what does that actually mean in practice in this case?
