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Astronomy Seminar Series artwork
May 1, 202311:30 am – 12:30 pm (CDT)

The Star that Refuses to Die


Curtis McCully (Las Cumbres Observatory)



Mitchell Institute for Fundamental Physics & Astronomy

College Station, Texas 77843

Event Details

White-dwarf supernovae (SNe) play a key role in cosmology and led to the discovery of the accelerating universe driven by dark energy. While a “normal” white-dwarf supernova fully destroys the exploding star, the case for SN 2012Z is more complex. SN 2012Z was a type Iax supernova, the largest class of peculiar white-dwarf supernovae. I will present observations of the full life cycle of SN 2012Z starting from detection of the progenitor system in pre-explosion images (the first for any white-dwarf supernova) to nearly 1500 days past peak brightness. Surprisingly, the supernova has remained brighter than the pre-explosion measurements at these late epochs. I will present a variety of physical mechanisms that could explain these measurements including radioactive decay of long lived isotopes, circumstellar interaction, shock heating of a companion star, and winds from a surviving bound remnant. I will also present simple models of the energetics of type Iax supernovae which favor a Chandrasekhar mass progenitor. As we begin to better understand white-dwarf explosions in general, we will use the discoveries about type Iax supernovae to inform our understanding of our cosmological standard(izable) candles, normal type Ia supernovae.

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