(Proposal ID) S10A-068 (PI) Maeda, Keiichi (Proposal Title) Properties of Type Ia Supernovae from Late-Time Spectroscopy (Abstract) We propose to perform FOCAS late-time spectroscopy and photometry of ~ 15 Type Ia supernovae (SNe Ia). Recent theoretical models suggest that asymmetry in the initial deflagration flame may be a key leading to the diverse properties of SNe Ia. It has been recently pointed out that the signature of this asymmetry should/can be seen in [Fe II]lambda7155 and [Ni II]lambda7378 in late-time spectra, although the size of the current sample is still too limited to draw quantitative conclusions. With additional ~ 15 SNe Ia, we will for the first time be able to test the hypothesis that the asymmetry is a generic feature in SNe Ia. Also, we will eventually see a hint of whether the degree of the asymmetry is dependent on the peak brightness. The abundance in the innermost region will be derived, which provides another strong diagnostic of the explosion mechanism. Especially, our targets include faint 1991bg-like SNe Ia, for which the late-time spectra are rare; this will be important to clarify the origin of the diversity. Adding to the "explosion mechanism" issues, our proposed observations are also useful to study the environment and progenitor scenarios, by investigating emission lines from the host galaxies and from the vicinity of SNe Ia.