My research topics include:
Classical and recurrent novae
A classical nova (CN) eruption is the result of a thermonuclear runaway that is triggered below the surface of a white dwarf (WD) accreting (mostly) hydrogen from a main sequence (MS) donor. It is observed as a sudden, highly energetic mass ejection, that declines over the course of several weeks to a few years. Classical and recurrent novae (RN) are distinguished by the number of times an eruption was observed to occur in the system. Recent studies of long-term evolution have shown that a cataclysmic variable (CV) system will undergo major changes over the course of Gyrs, effecting the outcome of the many eruptive features and timescales ruled by the accretion rate which has recently been shown to vary during a single cycle as well as secularly. I am interested in determining the occurrence rate of novae for initial donor masses, as well as the differences and similarities of the various WD+MS possible combinations.
Recurrent novae as progenitors of SNIa
Type Ia supernovae (SNIa) are standard candles used to measure vast cosmological distances. It has been established that the reason for the display of a constant light curve and spectrum is due to SNIa being the result of the detonation (and explosion) of a Chandrasekhar mass WD. However, the source of such a detonation is controversial, with a handful of still not entirely proved theories, one of which is RNe. Studies have shown that RNe that occur on the surface of high mass WDs, typically >1.25 Solar masses that accrete matter from a donor at a very high accretion rate, will produce rapidly recurring, weak eruptive novae, resulting in the WD growing in mass. I am currently investigating the possibility of RNe being the progenitor of SNIa, from a number of perspectives, including the timescales, the donor type and mass, the permitted mass transfer regimes, and the long-term evolution which determines the mass transfer rate.
Wind induced novae in symbiotic systems
Nova eruptions have been observed to occur in symbiotic systems, i.e., systems in which the donor is an evolved giant on the red giant branch (RGB) or asymptotic giant branch (AGB). These eruptions are known as “symbiotic nova” and are typically weaker than CNe and RNe in CVs. Recent numerical modelling implies that despite the very different types of progenitor systems and the typically lower eruption amplitude, the physical processes that lead to these eruptions are the same processes that occur in classical and recurrent nova. The mass may be transferred to the WD via wind, or Roche-lobe overflow (RLOF) or both, possibly allowing for an entire regime of accretion rates rarely seen in CVs, that allow the WD to grow. I am interested in defining the possible accretion rates that may be generated due to these mechanisms, as well as understanding the influence of changes in other input parameters on the outcome.
