Thermonuclear Supernovae: Geometry as the Rosetta Stone of Explosions and Progenitors, with Implications for Precision Cosmology

Type Ia supernovae (SN) play an essential role in measuring the accelerating expansion of the Universe, produce half of the Universe’s heavy metals, and help astronomers to study cosmology and many aspects of fundamental physics. Although this type of supernova is known to involve the explosion of a compact white dwarf star, there is an enormous diversity of variations of Type Ia SNe, and astrophysicists have developed an even large diversity of explosion scenarios. A research team at Florida State University (FSU) will incorporate new observations from the James Webb Space Telescope (JWST) and ground-based high-cadence spectropolarimetry programs into new theoretical models that capture the geometry of Type Ia SNe explosions. For the first time, it is possible to obtain the full 3-D image of SNe Ia by combining multi-messenger and time-domain observations from days to years after the explosion Geometry is sensitive to the companion star and the circumstellar environment, the physics of the ignition and flame propagation, and models make new and clear new qualitative and quantitative predictions. Supernovae and cosmology capture the public imagination and drive forefront science. The FSU planetarium provides an ideal platform to raise public curiosity about the production of chemical elements in SNe and their impact on every aspect of human life. A central objective is to explain how research makes progress through trial and error, models and experimental tests, etc. The audience are new FSU and middle- and high-school students, educators, and the public. The presenters will be the principal investigators, his students and the postdoctoral researcher. The primary goal of the project is to understand the unique geometrical imprints of the explosion physics and progenitor systems on the expanding envelope. An important derivative will be the directional dependence of the brightness, which is needed for precision cosmology. This study makes full use of time-domain and multi-messenger astronomy combined with full multi-D non-local-thermal equilibirum radiation transport, instead of relying on the conventional approach of spherical averaging. In this way, the information conveyed by the polarization and asymmetry of line profiles can be exploited. Instead of indiscriminately covering the vast parameter space populated by medium-quality data, the project will map the path to a new state of the art of simulations based on the best available data, namely the few SNe Ia with extent multi-messenger data plus two specific SNe Ia with ongoing JWST and ground-based high-cadence spectropolarimetry programs. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.