Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

The Physical Properties of PS1-12sk and the Implications to Its Progenitor System

Kai-Li Mi, Shan-Qin Wang, Wen-Pei Gan, Qiu-Ping Huang, Tao Wang, En-Wei Liang

Abstract

PS1-12sk is a type Ibn supernova (SN) found at the host environment showing no obvious ongoing star formation, which challenges the massive star explosion scenario. We use the ejecta-circumstellar medium (CSM) interaction (CSI) and the CSI plus $^{56}$Ni models in the context of double white dwarf (WD) merger to fit the bolometric light curve (LC) of PS1-12sk, since the He emission lines at the photospheric phases indicated the interaction between the SN ejecta and He-rich CSM. We find that the CSI model failed to explain the LC, but the CSI plus $^{56}$Ni model can account for the bolometric LC. The derived masses of the two WDs and $^{56}$Ni are $\sim 0.70 M_\odot$, $\sim 0.40 M_\odot$, and $\sim 0.09\,M_\odot$, respectively. The facts that the ejecta mass ($\sim 0.984 M_\odot$) is well below the Chandrasekhar limit ($\sim 1.4 M_\odot$) and that the $^{56}$Ni mass is comparable to the $^{56}$Ni yields of the explosions of some sub-Chandrasekhar explosion models support the scenario that PS1-12sk might be from a sub-Chandrasekhar explosion induced by the merger of two low-mass WDs. The derived innermost radius ($\sim 13.81 \times 10^{12}$ cm) and the mass of the CSM ($\sim 0.116 M_\odot$) disfavor the possibility that the CSM was formed in the merger phase. We suggest that the flybys before the merger can account for the position and mass of the CSM.

The Physical Properties of PS1-12sk and the Implications to Its Progenitor System

Abstract

PS1-12sk is a type Ibn supernova (SN) found at the host environment showing no obvious ongoing star formation, which challenges the massive star explosion scenario. We use the ejecta-circumstellar medium (CSM) interaction (CSI) and the CSI plus Ni models in the context of double white dwarf (WD) merger to fit the bolometric light curve (LC) of PS1-12sk, since the He emission lines at the photospheric phases indicated the interaction between the SN ejecta and He-rich CSM. We find that the CSI model failed to explain the LC, but the CSI plus Ni model can account for the bolometric LC. The derived masses of the two WDs and Ni are , , and , respectively. The facts that the ejecta mass () is well below the Chandrasekhar limit () and that the Ni mass is comparable to the Ni yields of the explosions of some sub-Chandrasekhar explosion models support the scenario that PS1-12sk might be from a sub-Chandrasekhar explosion induced by the merger of two low-mass WDs. The derived innermost radius ( cm) and the mass of the CSM () disfavor the possibility that the CSM was formed in the merger phase. We suggest that the flybys before the merger can account for the position and mass of the CSM.
Paper Structure (7 sections, 4 figures, 3 tables)

This paper contains 7 sections, 4 figures, 3 tables.

Table of Contents

  1. Introduction
  2. Modeling the Bolometric Light Curves of PS1-12sk.
  3. Discussion
  4. The implications of the derived parameters of PS1-12sk
  5. The origin of the CSM of PS1-12sk
  6. Conclusions
  7. Some extra material

Figures (4)

  • Figure 1: The synthesized bolometric LC of PS1-12sk.
  • Figure 2: The best fit (solid curves) of the bolometric light curve of PS1-12sk using the CSI model for the white dwarf merger scenario. Shaded regions indicate 1$\sigma$ bounds of the parameters.
  • Figure 3: The best fit (the solid curves) of the bolometric LC of PS1-12sk using the CSI plus $^{56}$Ni model (for the WD merger scenario). The dashed and dotted lines represent the contributions from CSI and $^{56}$Ni decay, respectively. The shaded regions indicate 1$\sigma$ bounds of the parameters.
  • Figure 4: The corner plot of the CSI plus $^{56}$Ni model. The solid vertical lines represent the best-fitting parameters, while the dashed vertical lines represent the medians and the $1\sigma$ bounds of the parameters.