  In the single degenerate (SD) scenario of type Ia supernovae (SNe Ia), the
collision of the ejecta with its companion results in stripping hydrogen rich
matter from the companion star. This hydrogen rich matter might leave its trace
in the light curves and/or spectra. In this paper, we perform radiation
hydrodynamical simulations of this collision for three binary systems. As a
result, we find that the emission from the shock-heated region is not as strong
as in the previous study. This weak emission, however, may be a result of our
underestimate of the coupling between the gas and radiation in the shock
interaction. Therefore, though our results suggest that the observed early
light curves of SNe Ia can not rule out binary systems with a short separation
as the progenitor system, more elaborate numerical studies will be needed to
reach a fair conclusion. Alternatively, our results indicate that the feature
observed in the early phase of a recent type Ia SN 2014J might result from
interaction of the ejecta with a red giant companion star. We also discuss the
dependence of spectral features of H alpha and Si II absorption lines on
viewing angles and investigate whether they can constrain the event rate of the
SD progenitor.
