Exploring the Energy Sources Powering the Light Curve of the Type Ibn Supernova PS15dpn and the Mass-loss History of the SN Progenitor

Abstract

PS15dpn is a luminous rapidly rising Type Ibn supernova (SN) discovered by Pan-STARRS1. Previous study has showed that its bolometric light curve (LC) cannot be explained by the 56 Ni model. In this paper, we used the 56 Ni model, the magnetar model, the circumstellar interaction (CSI) model, and the CSI plus 56 Ni model to fit the bolometric LC of PS15dpn. We found that the 56 Ni model can fit the bolometric LC but the parameters are unrealistic, and that the magnetar model, the CSI model, and the CSI plus 56 Ni model can match the data with reasonable parameters. Considering the fact that the emission lines indicative of the interaction between the ejecta and the circumstellar medium (CSM) have been confirmed, and that the SNe produced by the explosions of massive stars can synthesize moderate amounts of 56 Ni, we suggest that the CSI plus 56 Ni model is the most promising model. Assuming that the CSM is a shell (wind), the masses of the ejecta, the CSM, and the 56 Ni are ( M ⊙ ), M ⊙ ( M ⊙ ), and M ⊙ ( M ⊙ ), respectively. The inferred ejecta masses are consistent with the scenario that the progenitors of SNe Ibn are massive Wolf–Rayet stars. Adopting the shell CSM scenario, the shell might be expelled by an eruption of the progenitor just ∼17–167 days prior to the SN explosion; for the wind scenario, the inferred mass-loss rate of the wind is ∼8.0 M ⊙ yr −1 , indicating that the wind is a “super-wind” having an extremely high mass-loss rate.