We explore the well-observed type IIP SN 2013ej with peculiar luminosity
evolution. It is found that the hydrodynamic model cannot reproduce in detail
the bolometric luminosity at both the plateau and the radioactive tail. Yet the
ejecta mass of 23-26 Msun and the kinetic energy of (1.2-1.4)x10^51 erg are
determined rather confidently. We suggest that the controversy revealed in
hydrodynamic simulations stems from the strong asphericity of the Ni-56 ejecta.
An analysis of the asymmetric nebular H-alpha line and of the peculiar
radioactive tail made it possible to recover parameters of the asymmetric
bipolar Ni-56 ejecta with the heavier jet residing in the rear hemisphere. The
inferred Ni-56 mass is 0.039 Msun, twice as large compared to a straightforward
estimate from the bolometric luminosity at the early radioactive tail. The bulk
of ejected Ni-56 has velocities in the range of 4000-6500 km/s. The linear
polarization predicted by the model with the asymmetric ionization produced by
bipolar Ni-56 ejecta is consistent with the observational value.Comment: 7 pages, 8 figures, 3 tables. Accepted for publication in MNRA
