The Life Cycle of Dust
NGC 6537, the Red Spider Nebula
The interstellar medium plays a central role in the evolution of galaxies as the birthsite of new stars and the repository of old stellar ejecta. The formation of new stars slowly consumes the ISM, locking it up for millions to billions of years. As these stars age, the winds from low mass, asymptotic giant branch (AGB) stars and high mass, red supergiants, and supernova explosions inject nucleosynthetic products of stellar interiors into the ISM, progressively increasing its metallicity. This constant recycling and associated enrichment drives the evolution of a galaxy's baryonic matter and changes its emission characteristics. To understand this recycling, our group studies the physical processes of the ISM, the formation of new stars, and the injection of mass by evolved stars, and their relationships on a galaxy-wide scale.
We use the life cycle of dust as a probe of these processes and study dust grains in a wide variety of environments of relevance, ranging from sites of dust production (AGB stars, red supergiants, post-AGB objects, planetary nebulae, but also more exotic locations such as quasar winds) via the interstellar medium to star forming regions, where the dust grains ultimately become part of stars and planetary systems again.
Using infrared spectroscopy and additional measurements at other wavelengths, we try to establish dust masses, grain sizes and grain temperatures, but also more detailed properties, such as mineralogical composition and lattice structure, and aim to correlate those the physical conditions the dust grains have experienced. Additional constraints are provided by in situ measurements of the properties of Solar System materials, including Interplanetary Dust Particles. We have close connections with the Isotope Geochemistry and Cosmochemistry group in the School of Earth, Atmospheric and Environmental Sciences performing these type of investigations. Ultimately, we aim to develop a dust evolution model consistent with the history of the Universe itself.