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تسجيل مستخدم جديدOptical studies of two stripped envelope supernovae SN 2015ap (Type Ib) and SN 2016P (Type Ic)
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We present the photometric and spectroscopic studies of a Type Ib SN 2015ap and a Type Ic SN 2016P. SN 2015ap is one of the bright (M$_{V}$ = $-$18.04 mag) Type Ib while SN 2016P lies at an average value among the Type Ic SNe (M$_{V}$ = $-$17.53 mag). Bolometric light curve modelling of SNe 2015ap and 2016P indicates that both the SNe are powered by $^{56}$Ni + magnetar model with $^{56}$Ni masses of 0.01 M$_{odot}$ and 0.002 M$_{odot}$, ejecta masses of 3.75 M$_{odot}$ and 4.66 M$_{odot}$, spin period P$_{0}$ of 25.8 ms and 36.5 ms and magnetic field B$_{p}$ of 28.39 $times$ 10$^{14}$ Gauss and 35.3 $times$ 10$^{14}$ Gauss respectively. The early spectra of SN 2015ap shows prominent lines of He with a W feature due to Fe complexes while other lines of Mg II, Na I and Si II are present in both SNe 2015ap and 2016P. Nebular phase [O I] profile indicates an asymmetric profile in SN 2015ap. The [O I]/[Ca II] ratio and nebular spectral modelling of SN 2015ap hints towards a progenitor mass between 12 $-$ 20 M$_{odot}$.
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Many young, massive stars are found in close binaries. Using population synthesis simulations we predict the likelihood of a companion star being present when these massive stars end their lives as core-collapse supernovae (SNe). We focus on stripped
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Stripped-envelope supernovae (SE-SNe) show a wide variety of photometric and spectroscopic properties. This is due to the different potential formation channels and the stripping mechanism that allows for a large diversity within the progenitors oute
r envelop compositions. Here, the photometric and spectroscopic observations of SN 2020cpg covering $sim 130$ days from the explosion date are presented. SN 2020cpg ($z = 0.037$) is a bright SE-SNe with the $B$-band peaking at $M_{B} = -17.75 pm 0.39$ mag and a maximum pseudo-bolometric luminosity of $L_mathrm{max} = 6.03 pm 0.01 times 10^{42} mathrm{ergs^{-1}}$. Spectroscopically, SN 2020cpg displays a weak high and low velocity H$alpha$ feature during the photospheric phase of its evolution, suggesting that it contained a detached hydrogen envelope prior to explosion. From comparisons with spectral models, the mass of hydrogen within the outer envelope was constrained to be $sim 0.1 mathrm{M}_{odot}$. From the pseudo-bolometric light curve of SN 2020cpg a $^{56}$Ni mass of $M_mathrm{Ni} sim 0.27 pm 0.08$ $mathrm{M}_{odot}$ was determined using an Arnett-like model. The ejecta mass and kinetic energy of SN 2020cpg were determined using an alternative method that compares the light curve of SN 2020cpg and several modelled SE-SNe, resulting in an ejecta mass of $M_mathrm{ejc} sim 5.5 pm 2.0$ $mathrm{M}_{odot}$ and a kinetic energy of $E_mathrm{K} sim 9.0 pm 3.0 times 10^{51} mathrm{erg}$. The ejected mass indicates a progenitor mass of $18 - 25 mathrm{M}_{odot}$. The use of the comparative light curve method provides an alternative process to the commonly used Arnett-like model to determine the physical properties of SE-SNe.
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