ASASSN-14ms: The Most Energetic Known Explosion of a Type Ibn Supernova and Its Physical Origin
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
AbstractASASSN-14ms may represent the most luminous Type Ibn supernova (SN Ibn) ever detected, with an absolute U-band magnitude brighter than 22.0 mag and a total bolometric luminosity >1.0 1044 erg s1 near maximum light. The early-time spectra of this SN are characterized by a blue continuum on which are superimposed narrow P Cygni profile lines of He i, suggesting the presence of slowly moving (1000 km s1), He-rich circumstellar material (CSM). At 12 months after maximum brightness, the He i line profiles become only slightly broader, with blueshifted velocities of 20003000 km s1, consistent with the CSM shell being continuously accelerated by the SN light and ejecta. Like most SNe Ibn, the light curves of ASASSN-14ms show rapid post-peak evolution, dropping by 7 mag in the V band over three months. Such a rapid post-peak decline and high luminosity can be explained by interaction between SN ejecta and helium-rich CSM of 0.9 M at a distance of 1015 cm. The CSM around ASASSN-14ms is estimated to originate from a pre-explosion event with a mass-loss rate of 6.7 M yr1 (assuming a velocity of 1000 km s1), which is consistent with abundant He-rich material violently ejected during the late WolfRayet (WN9-11 or Opfe) stage. After examining the light curves for a sample of SNe Ibn, we find that the more luminous ones tend to have slower post-peak decline rates, reflecting that the observed differences may arise primarily from discrepancies in the CSM distribution around the massive progenitors.
