Colloquium on 10 July 2014
Kepler’s supernova remnant: recent perspectives


Title: Kepler’s supernova remnant: recent perspectives
Speaker: Ravi Sankrit
Date: Thursday, 10 July 2014
Time: 11:00 - 12:00
Venue: SAAO Auditorium


Kepler’s supernova remnant (SN 1604) has proved to be the most puzzling of the handful of historical remnants in the Galaxy. The remnant was observationally recovered in the mid-20th century, but only within the last decade was the Type Ia nature of the supernova definitively established. Kepler belongs to a rare subclass of Type Ia objects that are surrounded by the circumstellar medium (CSM) of the progenitor system. The existence of the CSM provides evidence that Kepler is the result of a single-degenerate (SD, a single accreting white dwarf) rather than a double-degenerate (DD, a merger of two white dwarfs) explosion.

We have recently obtained second epoch Hubble Space Telescope images of Kepler, about 10 years after the first epoch. We are also scheduled to obtain Gemini-GMOS spectroscopy of several filaments in the remnant and of stars towards its center. The filament data will allow for an accurate measurement of the distance to Kepler, which is necessary for determining the supernova explosion energy. If the SD scenario is correct, the stellar data will provide us the best chance of identifying the companion to the supernova progenitor. With our recent and ongoing work as the central focus, I will present an overview of our current understanding of Kepler’s remnant and its origin. The topic has taken on an added dimension of interest because knowledge about Type Ia supernovae inform our inferences about the expansion and acceleration of the universe.

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