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ABSTRACT We present high-cadence photometric and low-resolution (R $$\sim$$ 400–700) optical spectroscopic observations of Type IIP supernova, SN 2018pq, which exploded on the outskirts of the galaxy IC 3896A. The optically thick phase (‘plateau’) lasts approximately 97 d, the plateau duration of normal Type IIP supernovae. SN 2018pq has a V-band absolute magnitude of $$-16.42 \pm 0.01$$ mag at 50 d, resembles normal-luminous supernova, and the V-band decline rate of 0.42 $$\pm$$ 0.06 mag 50 d$$^{-1}$$ during the plateau phase. A steeper decline rate of 11.87 $$\pm$$ 1.68 mag 100 d$$^{-1}$$ was observed compared to that of typical Type IIP supernovae during the transition between plateau to nebular phase. We employ detailed radiative transfer spectra modelling, tardis, to reveal the photospheric temperature and velocity at two spectral epochs. The well-fitted model spectra indicate SN 2018pq is a spectroscopically normal Type IIP supernova. Semi-analytical light curve modelling suggests the progenitor as a red supergiant star with an ejecta mass of $$\sim$$11 $${\rm M}_\odot$$ and an initial radius of 424 $${\rm R}_\odot$$. On the contrary, hydrodynamical modelling suggests a higher mass progenitor between 14 and 16 $${\rm M}_\odot$$.
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Low luminosity Type II supernovae – IV. SN 2020cxd and SN 2021aai, at the edges of the sub-luminous supernovae class
ABSTRACT Photometric and spectroscopic data for two Low Luminosity Type IIP Supernovae (LL SNe IIP) 2020cxd and 2021aai are presented. SN 2020cxd was discovered 2 d after explosion at an absolute magnitude of Mr = −14.02 ± 0.21 mag, subsequently settling on a plateau which lasts for ∼120 d. Through the luminosity of the late light curve tail, we infer a synthesized 56Ni mass of (1.8 ± 0.5) × 10−3 M⊙. During the early evolutionary phases, optical spectra show a blue continuum ($$T\, \gt $$8000 K) with broad Balmer lines displaying a P Cygni profile, while at later phases, Ca ii, Fe ii, Sc ii, and Ba ii lines dominate the spectra. Hydrodynamical modelling of the observables yields $$R\, \simeq$$ 575 R⊙ for the progenitor star, with Mej = 7.5 M⊙ and $$E\, \simeq$$ 0.097 foe emitted during the explosion. This low-energy event originating from a low-mass progenitor star is compatible with both the explosion of a red supergiant (RSG) star and with an Electron Capture Supernova arising from a super asymptotic giant branch star. SN 2021aai reaches a maximum luminosity of Mr = −16.57 ± 0.23 mag (correcting for AV = 1.92 mag), at the end of its remarkably long plateau (∼140 d). The estimated 56Ni mass is (1.4 ± 0.5) × 10−2 M⊙. The expansion velocities are compatible with those of other LL SNe IIP (few 103 km s−1). The physical parameters obtained through hydrodynamical modelling are $$R\, \simeq$$ 575 R⊙, Mej = 15.5 M⊙, and E = 0.4 foe. SN 2021aai is therefore interpreted as the explosion of an RSG, with properties that bridge the class of LL SNe IIP with standard SN IIP events.
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- PAR ID:
- 10358404
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Date Published:
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Volume:
- 513
- Issue:
- 4
- ISSN:
- 0035-8711
- Page Range / eLocation ID:
- 4983 to 4999
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1093/mnras/stac1182
