Abstract
We collected ultraviolet, optical, and near-infrared photometry together with optical and near-infrared spectra of SN 2009N. The optical spectra had narrow features with low velocities, typical of subluminous SNe II-P. The bolometric luminosity during the plateau phase was in between those of the subluminous and normal SNe II-P. The NIR spectra of SN 2009N contain features typical of SNe II-P, with the exception of the appearance of a feature at ∼ 1.055 μ m +48 days after the explosion. Via spectral modeling we found that this line is probably due to high-velocity He i λ 10830 The presence of this line, together with a HV component of Hα, can be an indicator of weak interaction of the ejecta with circumstellar material. We estimated the distance to SN 2009N using multiple versions of both the expanding photosphere method and the standardized candle method as D=21.6 ± 1.1 Mpc (μ=31.67 ± 0.11). The produced nickel mass was estimated to be 0.020 ± 0.004 M_sun. We determined the physical properties of the progenitor at the explosion via hydrodynamical modeling. The total explosion energy (∼ 0.48 {foe}) is in between the values typical of subluminous and normal SNe II-P. The pre-supernova mass (∼ 13-13.5 M_{sun}) is consistent with that of red supergiant stars, while the relatively small estimated radius at the time of the explosion (R_{ini}≈ 287 R_{sun}) can point to a yellow supergiant star.
