The Study For The Dust And Energy Source Of The Type ?bn SNe

The circumstellar medium(CSM)of type ?bn supernovae(SNe)comprise a large amount of helium atoms.The observed spectra clearly show strong He abso-rption lines and emission lines.The infrared and optical spectral energy distribu-tions(SEDs)and multi-band light curves of type ?bn SNe provide important clues for studying the properties of the dust around them and energy sources.This paper presents the works focusing on the dust formation and energy sources of SNe ?bn in details.We first present our study for the evidence of the dust formation of four SNe ?bn(SN 2010al,OGLE-2012-SN-006,LSQ13ddu and SN 2015G)having the op-tical and near-infrared observations.We analyzed their optical and near-infrared SEDs at different epochs,and fitted them with the blackbody model,finding that the SEDs of three SNe(SN 2010al,LSQ13ddu,and SN 2015G)can be fitted with this model.This indicates that no obvious evidence for the infrared excess.In contrast,the SEDs of OGLE-2012-SN-006 shows significant infrared excesses,which have been generally believed to be from the dust surrounding the SNe.We use the two-component(blackbody and dust)model to fit the SEDs of OGLE-2012-SN-006,demonstrating that the graphite model can fit its SEDs,and the derived mass and temperature of the dust are 0.5-2×10^-3 M?and 1200-1300 K,respectively.Our calculation also shows that the dust had been produced before the SN explosion.We also use the two-component model to fit the SEDs of SN 2010al,LSQ13ddu and SN 2015G and find that the upper limits of their dust masses are 1.5×10^-5 M?,5.9×10^-7 M?and 2.4×10^-7 M?,respectively.The second work of the thesis is the study for the energy sources of OGLE-2012-SN-006 which is a SN ?bn.We find the ⁵⁶Ni plus the ejecta-circumstellar medium(CSM)interaction model can fit its multi-band light curves.Our fits show that the luminosity around the peaks of the light curves was from the ejecta-CSM interaction,and the post-peak plateau of the light curves was powered by the ⁵⁶Ni cascade decay.For the wind(shell)model,the ejecta mass is 23.52 M?(7.85 M?),the mass of the ⁵⁶Ni is 0.26 M?(0.56 M?),the CSM mass is 1.83 M?(8.90 M?),the ejecta velocity is 11400 km s^-1(10800 km s^-1).Furthermore,we demonstrate that the peak bolometric luminosity of the SN is about 10⁴⁴ erg s^-1,which is comparable to that of super-luminous SNe.Finally,we give an outlook of the prospect for the observations and theoretical studies of SNe ?bn.