Desiree Harvell
Desiree pictured with her poster at the 2022 AAS winter meeting.
Seeking Hidden Helium in Stripped Envelope Supernovae
Abstract: The classification of core-collapse Type Ib and Ic supernovae (SNe) are defined by their spectra. Type Ib spectra contain Helium absorption features and Type Ic do not. It is an open question whether the lack of a helium detection in Type Ic SNe means there is no helium in the ejecta, or if there is helium in the outer layers that fails to impart a spectral signature. Stellar evolutionists have found difficulty in removing the helium layer in a stripped envelope star before a supernova (SN) event. Therefore, finding out why the potential helium goes undetected can benefit stellar evolutionists in their understanding of the stellar life cycle. We investigate the potential for “hidden helium” in stripped envelope SNe with the usage of simulated SN ejecta models. The radioactive 56Ni produced in the SN explosion is the main source of radiation that will stimulate the elements that appear on the spectra so changing the distribution may be highly influential. We vary the 56Ni distribution in a striped envelope explosion that contains helium in the outer layers of the ejecta. We hypothesize that a centralized 56Ni distribution will potentially result in weaker helium absorption features in the spectra. The findings of the experiment aim to answer if is possible for helium to still remain in the outer layers of Type Ic SN ejecta.