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High-Energy Astrophysics American and Soviet Perspectives/Proceedings from the U.S.-U.S.S.R. Workshop on High-Energy Astrophysics (1991) / Chapter Skim
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THE SHOCK BREAKOUT IN SN1987A MODELLED WITH THE TIME-DEPENDENT RADIATIVE TRANSFER
Pages 39-45

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From page 39...
... BARTUNOV Sternberg Astronomical Institute ABSTRACT The fully implicit high-order scheme has been developed for the time dependent multi-group radiative transfer coupled with implicit hydrody namics. The application of this scheme to the SN1987A explosion shows that shorter after the shock breakout a dense shell forms.
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From page 40...
... In particular, the effective temperature reaches the maximum value of about Sx 105K (The run on our 1 Mflops computer uses 150 Lagrangian mass zones, 20 geometrically spaced frequency groups and for optical depth T greater than 15-30, we switch to the equilibrium diffusion. The results, presented in Figures 1 and 2, are obtained in ~ 1 hour of CPU time.
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From page 41...
... It is the result of our calculation with the simplified assumption of "grey" opacity and the crude treatment of the Compton effect The most important qualitative difference of these new calculations from the results obtained in equill~irum diffusion approximation is the
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From page 42...
... In Figure 4 we present the formation of the dense shell in Eulerian coordinates, and Figure 5 shows the structure of the outermost layers of SN1987A in Lagrangian coordinates for the moment when the density peak looks most prominent. The layer containing the density peak has a mass of about 2 x 10-6 M<3 and the optical thickness ~ ~ 10.
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From page 43...
... , 480000 K shell is certainly Rayleigh-Taylor and thermally unstable, and it should fragment into small blobs. Further calculations, with other parameters of presupernova models and more accurate treatment of the Compton effect and the influence of lines on the opacity, are expected to show how the shell properties and the emergent spectra can vary.
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From page 44...
... M<, Igp gem-3 _9 -11 FIGURE 5 Distnbutions of density p, temperature ~ velocity v, and optical depth ~ near the edge of SN1987A envelope at time t = 4919 s (step 2600~.
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From page 45...
... 1971. Numencal initial value problems in ordinary dilierential equations.
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Key Terms

  • shock breakout
  • outermost layers
  • equilibrium diffusion
  • dense shell
  • radiation transport

  • light speed
  • time dependent
  • shock cumulation
  • effective temperature
  • compton effect

  • mflops computer
  • hydrostatic model
  • code calls
  • implicit gasdynamic
  • shell forms

  • initial hydrostatic
  • excellent agreement
  • special code
  • mass zones
  • step treatment

  • calculated light
  • degenerate stellar
  • implicit hydrody
  • numencal initial
  • transport accounting

  • light curse
  • retardation effect
  • shell properties
  • carbon burning
  • geometrically spaced


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