Novae, and their Potential as Progenitors of Type Ia Supernovae
Dr M Darnley
Novae, particularly the Recurrent Novae (RNe) that harbour either sub-giant or red giant secondary donor stars have long been touted as potential progenitors of Type Ia Supernovae (SNe), via the single-degenerate (SD) channel. Studies of nearby SN Ia have in some cases pointed towards a SD progenitor, whereas others have shown evidence of a double degenerate (DD) route, but the vast majority have an uncertain origin. More recently, it has been proposed that various pathways (from both SD and DD channels) may actively contribute to the observed SN Ia population, and that the dominance of any pathway may depend on the galaxy morphology or parent stellar population.
While the Nova rate, and hence size of the Nova population, of any galaxy can be relatively easily determined, the proportion of those Novae that contain either sub-giant or red giant donors (the potential SN Ia progenitors) is unknown. In recent years, the Nova group at the ARI has been working to determine the extent of this population, in order to evaluate the contribution Novae may make to the overall SN Ia rate for a given galaxy. Our approach is two fold; studying individual Novae and RNe, and their progenitors, in the Galaxy in great detail, while also surveying the entire Nova population and their progenitors in nearby galaxies, such as M31.
The work of a PhD student in this area would be broadly observational, with the Liverpool Telescope (LT) providing the majority of the photometric and spectroscopic observations of erupting novae, with progenitor work generally utilising archival data, in particular from the Hubble Space Telescope. A number of possible projects are available in this area, some focusing Galactically, some extragalactically, with different emphases on imaging and spectra. All of the projects would involve the PhD student running all or part of a large Nova observing programme on the LT and reacting to new eruptions. The PhD student will have the opportunity to work with a number of our close collaborators, here in the UK, and internationally.