A subluminous Type IIP supernova 2008in having properties unknown so far

Abstract

Supernova (SN) 2008in is a Type IIP event, which occurred in the outskirts of the nearby and nearly face-on spiral galaxyM61. The spectroscopic observations of this event suggest that it resembles those of the archetypal low-luminosity Type IIP SNe 1997D and 1999br. However, the extensive photometry reveals that its light curve is quite di_erent from that of low-luminosity events. The derived bolometric flux also indicates that the radioactive ⁵⁶Ni, produced during this process is significantly higher than that produced in case of low-luminosity events. Adopting an interstellar extinction of AV~ 0.30 mag along the SN line-of-sight and a distance of 13.19 Mpc, the estimated value of ejected ⁵⁶Ni mass is ~0:015Mʘ. The prescription of Litvinova & Nadezhin indicates that the pre-SN radius of the SN 2008in was ~126Rʘ and the explosion energy is of ~5.4 x 10⁵° erg. This value is consistent with the explosion energy determined through the radiation-hydrodynamical simulations of core-collapse IIP SNe. These parameter values are comparatively smaller than those of normal type IIP events. The estimated amount of total ejected mass is ~16.7Mʘ. Assuming the mass of compact remnant ~1.5-2.0Mʘ, we can confine the zero age main sequence mass of the progenitor within 20Mʘ