Research Projects

The evolution of stars is governed by factors such as initial mass, metallicity, mass loss, convection, and rotation. These influence nuclear burning, internal mixing, and shell structure, leading to significant chemical and structural diversity. Given the complexity of these channels, stellar evolution simulations often introduce stochasticity in elemental abundances. In massive stars, nuclear burning occurs in the hot core and surrounding compositional shells. Shell merging events—where unstable burning mixes layers of different composition—further diversify internal metal distributions, potentially altering the star’s path toward core collapse (CC) and affecting the outcome of the supernova (SN) explosion. These events also impact late-stage mass loss and the properties of the circumstellar medium (CSM). Rotation adds complexity by enhancing mixing, redistributing angular momentum, and boosting mass loss. Metallicity, through its effect on opacity and radiation transport, regulates radiatively driven winds. Winds from evolved stars—such as red supergiants (RSGs), Wolf-Rayet (WR) stars, and luminous blue variables (LBVs)—are key sources of interstellar enrichment. These winds, enriched by nuclear burning and shell mixing, inject metals, molecules, and dust into the interstellar medium (ISM). Massive stars end their lives in core-collapse supernovae (CCSNe), ejecting enriched interiors. The explosions, shockwaves, and cooling enable dust condensation. The type and composition of this dust—silicates, carbon grains, or oxides—depend on the progenitor’s properties. Supernovae are major dust contributors in galaxies. Variations in progenitor properties introduce diversity in dust formation, influencing grain size, composition, and distribution, with downstream effects on star formation and galaxy evolution. This project investigates how stochasticity in abundances, winds, metallicity, and rotation influences dust formation during pre-SN and SN phases. Using state-of-the-art stellar evolution codes and dust formation models, we will study finely spaced grids of progenitor models with varying properties, coupled to their dust formation channels. Our goal is to build a comprehensive database to address key uncertainties in SN dust production timelines and compositions, combining theory, simulations, and observations. This work complements ongoing James Webb Space Telescope (JWST) programs detecting dust in CCSNe and syncs with upcoming LSST (Legacy Survey of Space and Time) surveys, which will detect numerous SNe. Our model results will help interpret and predict these observations. We aim to: predict dust formation rates and compositions across progenitor types; link stellar evolution to CSM properties; model dust production by SN subtype; and quantify the contribution of massive stars to the cosmic dust budget. This will converge theory and observation, enriching our understanding of the cosmic matter cycle. Research questions: • Why and how do some massive stars create a dense circumstellar shell? What drives the variation in mass-loss rates and eruptive winds in those stars?
• What processes cause the stochasticity in the quantity of metals produced inside the massive stars? Do these processes determine the nature and probability of their explosion as supernovae?
• How much dust can form in pre-explosion and post-explosion winds in massive stars? How do the composition and mechanism of production vary among supernova subtypes?
• Can supernovae be the primary source of the large dust masses in the early universe? How are the stellar evolution pathways reflected in dust masses across different metallicities?