Enlightening supernovae
Supernovas occur mainly in two ways — the core collapse of massive stars, and the overloading of old white dwarfs with captured material. Supernovae produced when white dwarf stars accumulate excess mass that triggers a runaway thermonuclear reaction in the star are called Type Ia supernovae. These events can be used as ‘standard candles’ to estimate distances to the relevant galaxy based on their apparent brightness. The LDSNPS (Linking the diversity of Type Ia supernovae to their progenitor systems) project undertook a programme of research to improve our understanding of how the stars explode, and how accurately they can be used to measure distances. By comparing new observations with predictions from the theory of the explosion mechanism, they aimed to answer two questions: is there more than one way to make an SN Ia, and does their observed diversity depend on their progenitor systems and host galaxy environments? Data from leading ground-based transient surveys provided properties (expansion velocities, presence of elements, and luminosities) of the supernovae to compare with theoretical explosion models. Some complete-burning explosion models were eliminated based on the presence of high-velocity unburned elements observed in the supernova. The supernova properties were also found to be sensitive to the properties of the galactic locations within which they explode. The detailed results of the two analyses can be found in two publications (Maguire et al. 2014, Monthly Notices of the Royal Astronomical Society and Maguire et al. 2015, Monthly Notices of the Royal Astronomical Society, submitted).
Keywords
Supernova, cosmology, white dwarf star, SN Ia, model
