Late Time Spectroscopy of Type Ia Supernovae: Determining the Explosion Mechanism and Elemental Production
National Aeronautics and Space Administration James Webb Space Telescope General Observer Program-Cycle 3
Subaward to PSI from University of Hawaii
PI: Chris Ashall (University of Hawaii)
Non PSI Personnel: Peter Hoeflich (Co-Principal Investigator, Florida State University), Melissa Shahbandeh (Co-Principal Investigator, Space Telescope Science Institute), James DerKacy (Co-Principal Investigator, Space Telescope Science Institute)
Project Description
Type Ia Supernovae (SNe Ia) are the thermonuclear explosions of white dwarf stars, which originate from binary star systems and synthesize roughly half of the iron-group elements in the universe. The nature of the progenitors and the explosion mechanism is an open question. Understanding SNe Ia is foundational for: the late stages of stellar evolution, the origins of the elements, and controlling systematic errors related to the use of SNe Ia as cosmological rulers. Observational estimates of the nuclear burning products in SNe Ia probe the progenitor and explosion. JWST provides an entirely new window of opportunity as there are spectral lines with unique information in the MIR. We request 20.8 hours of time to obtain 3 Medium resolution MIRI spectra 100-500d past maximum light for the nearest SN Ia discovered in Cycle 3. The progenitor and explosion mechanism will be constrained using spectra acquired in three physical regimes: 1) 100-200d which measures radioactive Co and the intermediate mass elements, 2) 250-350d where hard gamma-rays, non-local effects, and the appearance of forbidden lines of neutron rich elements probe the progenitor density, 3) 400-500d where positrons deposit energy locally revealing the radioactive cobalt distribution. One of goals of JWST is to reveal the origin of heavy elements and how they feedback into the universe. The sensitivity and resolution of MIRI will produce resolved line profiles, probing the element distribution. MIRI spectra will also show many isolated forbidden lines of isotopes with known wavelengths. The atomic physics learned will provide insight into many transients to come.
