Supernovae (SNe) are huge stellar explosions and excellent sources of metal
enrichment in the Universe. They are observationally classified into two main
subtypes, hydrogen deficient and hydrogen rich based on the absence/presence
of hydrogen in their early time spectra, respectively. In this thesis we focus on
hydrogen deficient SNe and investigate their properties in optical wavelengths.
During October 2014 to May 2018, we have carried out observing campaigns of
several hydrogen deficient SNe using multiple observational facilities in the optical
wavelength for nearly 350 partial nights. For this thesis we have picked three SNe
(SN 2014dt, M12045 and PS15bgt) for a detailed analysis that had an excellent
high cadence data set covering each phase of the SN evolution. The similarity
between these three SNe is that they are devoid of any hydrogen features in their
early spectra but the physical mechanism of explosion are completely different.
SN 2014dt belongs to a rare sub-class of type Iax events which are expected
to come from thermonuclear runaway of CO white dwarf whereas M12045 and
PS15bgt belong to type Ib sub-class resulting from the explosion of a single mas-
sive star or a low mass progenitor in a binary system. Based on our analysis we
characterized SN 2014dt as a bright type Iax SN (M
v= -18.33±0.02 mag) which synthesizes 0.14 M of
56 Ni during the explosion. SN 2014dt displayed typical
characteristics of the type Iax class with low photospheric velocities (1000-5000km s−1) and hence the low energy budget (∼0.41×10 51 erg). The nebular spec-
tra of SN 2014dt reveals interesting facts about the plausible progenitor scenario
and indicates that it is a result of an incomplete eruption of a white dwarf which
has left behind a remnant. The late time flux in NIR is expected to come from
the bound remnant with an extended optically thick super-Eddington wind. Our
late time data as well as the NIR data of Foley et al.2016 supports the bound
remnant mechanism for SN 2014dt. The nebular phase spectra of two type Ib
SNe are studied in this thesis, M12045 and PS15bgt reflect the asymmetric nature
of explosion. The nebular phase observations have allowed to put for tight limits
on the main sequence progenitor masses. M12045 supports a massive progenitor
and PS15bgt is most likely outcome of a binary progenitor system. We also see
that both the type Ib SNe are fast decliners indicating a lower amount of 56 Ni
synthesized during the explosion and hence more massive progenitors. Future
dedicated observations of the type Iax class will throw light on the nature of the explosion and progenitors.