5 research outputs found
The Impact Of Stellar Convection Criteria On Population Iii Supernovae Nucleosynthesis
Population III stars are the first stars formed after the Big Bang, comprised of primarily
hydrogen and helium and lack heavy elements from previous generations. Using the
one-dimensional radiation-hydrodynamics code BOOM, a grid of eighteen stellar models
with masses of 15-80 solar masses , are exploded under a low and high explosion energy criteria.
Three types of central compact remnants are considered. The 3208 isotope TORCH nuclear
reaction network is used to calculate the nucleosynthesis that occurs during the
supernovae. The two convection criteria, Ledoux and Scharzschild, produce vastly
different stellar structures and thus produce different nucleosynthetic trends. When
comparing the numerically calculated abundances to observed extremely metal poor stars
([Fe/H] \u3c â3), it is found that even using abundances from both the Schwarzschild and
Ledoux convection model a fit was not possible. The overall Ni-56 production claculated
for a given distribution and the peak production of Ni-56 is compared to observationally
calculated values from Population II supernovae. We show that for high energy
Schwarzschild models, integrated over a Salpeter initial mass function, the yields
approach that of the more compact lower energy Ledoux series, but heavier elemental
abundances of these metal poor stars need to be observed and determined to better fit the
data. The produced nickel for both series is high compared to observational work and is
likely to be lessened for larger central remnants
How much H and He is "hidden" in SNe Ib/c? -- II. Intermediate-mass objects: a 22 M progenitor case study
Stripped envelope supernovae are a sub-class of core collapse supernovae
showing several stages of H/He shell stripping that determines the class:
H-free/He-poor SNe are classified as Type Ic, H-poor/He-rich are Type Ib, and
H/He-rich are Type IIb. Stripping H/He with only stellar wind requires
significantly higher mass loss rates than observed while binary-involved mass
transfer may usually not strip enough to produce H/He free SNe. Type Ib/c SNe
are sometimes found to include weak H/He transient lines as a product of a
trace amount of H/He left over from stripping processes. The extent and mass of
the H/He required to produce these lines is not well known. In this work, a 22
M progenitor model is stripped of the H/He shells in five steps prior
to collapse and then exploded at four explosion energies. Requiring both
optical and NIR He I lines for helium identification does not allow much He
mass to be hidden in SE--SNE. Increasing the mass of He above the CO core
delays the visibility of O I 7774 in early spectra. Our SN Ib-like models are
capable of reproducing the spectral evolution of a set of observed SNe with
reasonable estimated accuracy. Our SN\,IIb-like models can
partially reproduce low energy observed SN IIb, but we find no observed
comparison for the SN IIb-like models with high .Comment: 19 pages, 15 figures. Accepted by MNRAS, awaiting publicatio
Less than 1% of Core-Collapse Supernovae in the local universe occur in elliptical galaxies
We present observations of three Core-collapse supernovae (CCSNe) in elliptical hosts, detected by the Zwicky Transient Facility Bright Transient Survey (BTS). SN 2019ape is a SN Ic that exploded in the main body of a typical elliptical galaxy. Its properties are consistent with an explosion of a regular SN Ic progenitor. A secondary g-band light curve peak could indicate interaction of the ejecta with circumstellar material (CSM). An H-emitting source at the explosion site suggests a residual local star formation origin. SN 2018fsh and SN 2020uik are SNe II which exploded in the outskirts of elliptical galaxies. SN 2020uik shows typical spectra for SNe II, while SN 2018fsh shows a boxy nebular H profile, a signature of CSM interaction. We combine these 3 SNe with 7 events from the literature and analyze their hosts as a sample. We present multi-wavelength photometry of the hosts, and compare this to archival photometry of all BTS hosts. Using the spectroscopically complete BTS we conclude that of all CCSNe occur in elliptical galaxies. We derive star-formation rates and stellar masses for the host-galaxies and compare them to the properties of other SN hosts. We show that CCSNe in ellipticals have larger physical separations from their hosts compared to SNe Ia in elliptical galaxies, and discuss implications for star-forming activity in elliptical galaxies.</p
Less Than 1% of Core-collapse Supernovae in the Local Universe Occur in Elliptical Galaxies
We present observations of three Core-collapse supernovae (CCSNe) in
elliptical hosts, detected by the Zwicky Transient Facility Bright Transient
Survey (BTS). SN 2019ape is a SN Ic that exploded in the main body of a typical
elliptical galaxy. Its properties are consistent with an explosion of a regular
SN Ic progenitor. A secondary g-band light curve peak could indicate
interaction of the ejecta with circumstellar material (CSM). An
H-emitting source at the explosion site suggests a residual local star
formation origin. SN 2018fsh and SN 2020uik are SNe II which exploded in the
outskirts of elliptical galaxies. SN 2020uik shows typical spectra for SNe II,
while SN 2018fsh shows a boxy nebular H profile, a signature of CSM
interaction. We combine these 3 SNe with 7 events from the literature and
analyze their hosts as a sample. We present multi-wavelength photometry of the
hosts, and compare this to archival photometry of all BTS hosts. Using the
spectroscopically complete BTS we conclude that of all
CCSNe occur in elliptical galaxies. We derive star-formation rates and stellar
masses for the host-galaxies and compare them to the properties of other SN
hosts. We show that CCSNe in ellipticals have larger physical separations from
their hosts compared to SNe Ia in elliptical galaxies, and discuss implications
for star-forming activity in elliptical galaxies.Comment: Comments are welcome. Submitted to Ap