Dieter H. Hartmann
Nova outburst is the nuclear explosion on the surface of a white dwarf, which is caused by mass accretion from its companion star in the binary system. It is commonly believed that novae in Andromeda Galaxy (M31) separate into two distinct populations: bulge and disk in the galaxy. These spatial distinctions in the galaxy appear to correlate with the two spectral types of novae (FeII type and He/N). However, recent observations of novae in our own galaxy, Milky Way has demonstrated spectral transformations from FeII to He/N and vice-versa, which calls the spectral distinction between two source classes into question. However, for M31 only one such case is known. Multi epoch spectroscopy is needed to address the questions whether novae in M31 also undergo spectral transformations and whether spatial distinction in the galaxy has any correlation with the spectral type of novae. We construct a spatial distribution model of the stars in M31 and its disk/bulge nova population in order to investigate possible selection effects during observations, that could play a role in spectral-spatial correlations.
Kaur, Amanpreet and Hartmann, Dieter H., "Spectral Transformations of Novae in Andromeda Galaxy" (2013). Graduate Research and Discovery Symposium (GRADS). 85.