Impact of clumping on core-collapse supernova radiation

There is both observational and theoretical evidence that the ejecta of core-collapse supernovae (SNe) are structured. Rather than being smooth and homogeneous, the material is made of over-dense and under-dense regions of distinct composition. Here, we have explored the effect of clumping on the SN...

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Bibliographic Details
Published in:Astronomy and astrophysics (Berlin) 2018-11, Vol.619, p.A30
Main Authors: Dessart, L., Hillier, D. J., Wilk, K. D.
Format: Article
Language:English
Subjects:
Astrophysics
Blanketing
Bolometers
Clumps
Collapse
Ejecta
Ejection
Light curve
Local thermodynamic equilibrium
Luminosity
Organic chemistry
Photosphere
Physics
Porosity
Radiation
radiation: dynamics
Radiative transfer
Recession
supernova: individual: SN 1987A
Supernovae
supernovae: general
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Summary:There is both observational and theoretical evidence that the ejecta of core-collapse supernovae (SNe) are structured. Rather than being smooth and homogeneous, the material is made of over-dense and under-dense regions of distinct composition. Here, we have explored the effect of clumping on the SN radiation during the photospheric phase using 1D non-local thermodynamic equilibrium radiative transfer and an ejecta model arising from a blue-supergiant explosion (yielding a Type II-peculiar SN). Neglecting chemical segregation, we adopted a velocity-dependent volume-filling factor approach that assumes that the clumps are small but does not change the column density along any sightline. We find that clumping boosts the recombination rate in the photospheric layers, leading to a faster recession of the photosphere, an increase in bolometric luminosity, and a reddening of the SN colors through enhanced blanketing. The SN bolometric light curve peaks earlier and transitions faster to the nebular phase. On the rise to maximum, the strongest luminosity contrast between our clumped and smooth models is obtained at the epoch when the photosphere has receded to ejecta layers where the clumping factor is only 0.5 – this clumping factor may be larger in nature. Clumping is seen to have a similar influence in a Type II-Plateau SN model. As we neglected both porosity and chemical segregation, our models underestimate the true impact of clumping. These results warrant further study of the influence of clumping on the observables of other SN types during the photospheric phase.
ISSN:0004-6361
1432-0746
1432-0756
DOI:10.1051/0004-6361/201833278