Observational study of core-collapse supernovae with diminishing hydrogen envelope

Abstract

Supernovae (SNe) are the giant stellar explosions that brie y outshines the whole galaxy and enhances chemical enrichment. The thesis highlights a group of SNe with diminishing Hydrogen envelope. This mostly comprises of two groups - the stripped envelope group (SE-SNe, type IIb, Ib and Ic SNe) which strips o their outer envelopes due to high stellar winds or accretion with a nearby companion and the interacting SNe (type IIn, Ibn SNe) group which gains outer envelope due to interaction with a nearby circumstellar medium (CSM). In this thesis, we studied in depth the photometric and spectroscopic analysis of this group and derived a correlation between the members. Type IIb are the group of SNe that initially shows H features but later on transitions, showing He features, type Ib SNe shows predominant He features and type Ic SNe are devoid of both H and He features. Heterogeneous light curves, sometimes double peaked attributing to shock breakout phase are seen among SE-SNe. The progenitors could be both single massive stars like Wolf Rayet (WR) or they may be in binary association, however, the exact progenitor scenario is still debatable. Also, the ejecta shows highly asymmetric con guration indicating either an asymmetric explosion or dust formation.