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Spectropolarimetric Analysis of the Supernova M12045

As a massive star nears the end of its lifetime, its core contracts and heats, producing helium, carbon, oxygen, neon, silicon, and iron through nuclear fusion. Since iron is the heaviest element that can be fused in a star, the force produced by nuclear fusion can no longer act against gravity and the star energetically collapses and explodes, spewing clouds of elements and producing a supernova. These events are particularly exciting and important as supernovae are one of the most dominant sources of elements in our universe and many of the elements in our bodies and on Earth were once supernova remnants.

By analyzing spectropolarimetric data, our team is able to extract information about the structure of supernova explosions that are located at an inconceivably substantial distance away from us. Our data comes from the Supernova Spectropolarimetry Project, which is a collaboration between our lab, San Diego State University, and the University of Arizona. The observatory at UArizona collected multiple epochs of spectropolarimetric data for over 100 supernovae shortly after discovery. Throughout the summer of 2022, I utilized Python to analyze a type Ib supernova discovered in 2014 named M12045, which lives over fifty million light years away in the barred spiral galaxy NGC 4080. Supernovae are classified according to their spectral features, and type Ib supernovae are characterized by strong helium lines and no hydrogen lines in their spectra. My analysis is consistent with this classification as the most prominent features in the spectra for M12045 were the helium 5876Å and 7065Å lines. Additionally, we saw the signature of an oxygen doublet at 6300Å and 6363Å emerge in later epochs. Plots of the polarization components with velocity also show an asymmetrical explosion geometry as they are nonlinear. This ongoing research greatly contributes to our understanding of supernova explosion mechanisms.