Special Talk

• Special Talks

  Speaker: James DerKacy (STScI)
  Title: Type Ia Supernova Physics in the JWST Era
  Abstract: Nebular-phase observations of Type Ia supernova from JWST have transformed our understanding of the physics and origins of these cosmologically important events. Here, I will discuss JWST MIR observations of two SNe Ia; the normal-bright SN 2021aefx and the underluminous SN 2022xkq. Both SNe show spectral lines indicative of high density burning, including line from multiple ionization states of 58Ni and hints of electron-capture isotopes such as Ti, V, Cr, and Mn. The high-density burning necessary to produce these lines require a massive progenitor for both SNe, which has important implications for which explosions scenarios are viable models of SNe Ia. Finally, I discuss how JWST SNe Ia observations at ultra-late phases (> 750 days) to create long-baseline time-series data inform our understanding of the flux redistribution at late times and help us probe the conditions of the highest density burning in the explosion.

  Speaker: Patrick Ogle (STScI)
  Title: Introducing the Giant Hypersonic Fossil Planetary Nebula SDSO1​​​​​​​
  Abstract: We present deep narrowband optical imaging observations of the unusual Galactic [OIII] nebula SDSO1, which we hypothesize is the bow shock from a fast-moving, 20-pc diameter, 400-kyr old planetary nebula. The nebula was hiding in plain sight, with its 3-deg long tail crossing the disk of the galaxy M31. We identify the central star as the symbiotic WD binary star EG Andromedae, moving at Mach 7 with respect to the interstellar medium. This may be the first identification of a fossil planetary nebula (FPN) in its final snowplow phase before dissolving into the interstellar medium. This finding has far-reaching implications for the evolution of PNe and ISM enrichment. We find several other candidate FPNe associated with fast-moving young planetary nebulae, demonstrating that double PNe may be ejected in succession from evolved main-sequence binary stars. This work was done in collaboration with a team of amateur astrophotographers with sensitive, high-performance 4-inch refracting telescopes.