(Proposal ID) S14B-148

(PI) Takaki Katsutoshi

(Proposal Title)
 Detailed Studies of Selected Envelope-stripped Core-collapse Supernovae

(Abstract)
We propose late-phase optical observation for four envelope-stripped core-
collapse supernovae (SNe), which have shown distinct properties in our early-
phase data and/or pre-discovery HST images. Late-phase SN spectra are fully 
nebular, displaying cooling emission lines of heavy elements present in the 
inner ejecta. For envelope-stripped SNe, we expect less contamination from the
 unburned H/He-rich envelope. Together with the early-phase data which have 
been obtained with our collaboration, we will estimate the physical properties 
of the explosion (^{56}Ni mass, ejecta mass, asphericity, expansion velocity 
of the core) more precisely for iPTF13bvn (Ib), SN 2013df (IIb), SN 2013ge 
(Ic) and SN 2014C (Ic), and figure out the properties of their progenitor 
stars within the regime of massive star evolution.