科研之友
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摘要
Exact bolometric light curves of supernova shock breakouts are derived based on the universal, non-relativistic, planar breakout solutions, assuming spherical symmetry, constant Thomson scattering opacity, kappa, and angular intensity corresponding to the steady-state planar limit. These approximations are accurate for progenitors with a scale height much smaller than the radius. The light curves are insensitive to the density profile and are determined by the progenitor radius R, and the breakout velocity and density, v(0) and rho(0), respectively, and kappa. The total breakout energy, E-BO, and the maximal ejecta velocity, v(max), are shown to be E-BO = 8.0 pi R-2 kappa(-1)cv(0) and vmax = 2.0v(0), respectively, to an accuracy of about 10%. The calculated light curves are valid up to the time of transition to spherical expansion, t(sph) approximate to R/4v(0). Approximate analytic expressions for the light curves are provided for breakouts in which the shock crossing time at breakout, t(0) = c/rho(0)v(0)(2), is << R/c (valid for R < 10(14) cm). Modifications of the flux angular intensity distribution and differences in shock arrival times to the surface, Delta t(asym), due to moderately asymmetric explosions, affect the early light curve but do not affect vmax and EBO. For 4v(0) << c, valid for large (red supergiant) progenitors, L alpha t(-4/3) at max(Delta T-asym, R/c) < t < t(sph) and R may be accurately estimated from R approximate to 2 x 10(13) (L/10(43) erg s(-1))(2/5)(t/1 hr)(8/15).
- 出版日期2012-3-10
