Supernovae from blue supergiant progenitors: What a mess!. (arXiv:1812.07620v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Dessart_L/0/1/0/all/0/1">Luc Dessart</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hillier_D/0/1/0/all/0/1">D. John Hillier</a>
Since the discovery of SN (supernova) 1987A, the number of Type II-peculiar
SNe has grown, revealing a rich diversity in photometric and spectroscopic
properties. In this study, using a single 15Msun low-metallicity progenitor
that dies as a blue supergiant (BSG), we have generated explosions with a range
of energies and 56Ni masses. We then performed the radiative transfer modeling
with CMFGEN from 1d until 300d after explosion. Our models yield light curves
that rise to optical maximum in ~100d, with a similar brightening rate, and
with a peak absolute V-band magnitude spanning from -14 to -16.5mag. All models
follow a similar color evolution, entering the recombination phase within a few
days of explosion, and reddening further until the nebular phase. Their
spectral evolution is analogous, mostly differing in line profile width. With
this model set, we study the Type II-pec SNe 1987A, 2000cb, 2006V, 2006au,
2009E, and 2009mw. Their photometric and spectroscopic diversity suggest that
there is no prototypical Type II-pec SN. These SNe brighten to maximum faster
than our model set, except perhaps SN2009mw. The spectral evolution of SN1987A
conflicts with other observations and with model predictions from 20d until
maximum: Halpha narrows and weakens while BaII lines strengthen faster than
predicted, which we interpret as signatures of clumping. SN2000cb rises to
maximum in only 20d and shows weak BaII lines. Its spectral evolution is well
matched by an energetic ejecta but the light curve may require asymmetry. The
persistent blue color, narrow lines, and weak Halpha absorption, seen in
SN2006V conflicts with expectations for a BSG explosion powered by 56Ni and may
require an alternative power source. In addition to diversity arising from
different BSG progenitors, we surmise that their ejecta are asymmetric,
clumped, and, in some cases, not solely powered by 56Ni decay [abridged].
Since the discovery of SN (supernova) 1987A, the number of Type II-peculiar
SNe has grown, revealing a rich diversity in photometric and spectroscopic
properties. In this study, using a single 15Msun low-metallicity progenitor
that dies as a blue supergiant (BSG), we have generated explosions with a range
of energies and 56Ni masses. We then performed the radiative transfer modeling
with CMFGEN from 1d until 300d after explosion. Our models yield light curves
that rise to optical maximum in ~100d, with a similar brightening rate, and
with a peak absolute V-band magnitude spanning from -14 to -16.5mag. All models
follow a similar color evolution, entering the recombination phase within a few
days of explosion, and reddening further until the nebular phase. Their
spectral evolution is analogous, mostly differing in line profile width. With
this model set, we study the Type II-pec SNe 1987A, 2000cb, 2006V, 2006au,
2009E, and 2009mw. Their photometric and spectroscopic diversity suggest that
there is no prototypical Type II-pec SN. These SNe brighten to maximum faster
than our model set, except perhaps SN2009mw. The spectral evolution of SN1987A
conflicts with other observations and with model predictions from 20d until
maximum: Halpha narrows and weakens while BaII lines strengthen faster than
predicted, which we interpret as signatures of clumping. SN2000cb rises to
maximum in only 20d and shows weak BaII lines. Its spectral evolution is well
matched by an energetic ejecta but the light curve may require asymmetry. The
persistent blue color, narrow lines, and weak Halpha absorption, seen in
SN2006V conflicts with expectations for a BSG explosion powered by 56Ni and may
require an alternative power source. In addition to diversity arising from
different BSG progenitors, we surmise that their ejecta are asymmetric,
clumped, and, in some cases, not solely powered by 56Ni decay [abridged].
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