A Comparative Modeling of Supernova 1993J

Abstract

The light curve of supernova (SN) 1993J is calculated using two approaches to radiation transport as exempliÐed by the two computer codes, STELLA and EDDINGTON. Particular attention is paid to shock breakout and the photometry in the U, B, and V bands during the Ðrst 120 days. The hydrodynamical model, the explosion of a 13 star that has lost most of its hydrogenic envelope to a com-M _ panion, is the same in each calculation. The comparison elucidates di †erences between the approaches and also serves to validate the results of both. STELLA includes implicit hydrodynamics and is able to model supernova evolution at early times, before the expansion is homologous. STELLA also employs multigroup photonics and is able to follow the radiation as it decouples from the matter. EDDINGTON uses a di †erent algorithm for integrating the transport equation, assumes homologous expansion, and uses a Ðner frequency resolution. Good agreement is achieved between the two codes only when compatible physical assumptions are made about the opacity. In particular, the line opacity near the principal (second) peak of the light curve must be treated primarily as absorptive, even though the electron density is too small for collisional deexcitation to be a dominant photon destruction mechanism. JustiÐcation is given for this assumption and involves the degradation of photon energy by "" line splitting,ÏÏ i.e., Ñuores-cence. The fact that absorption versus scattering matters to the light curve is indicative of the fact that departures from equilibrium radiative di †usion are important. A new result for SN 1993J is a prediction of the continuum spectrum near the shock breakout (calculated by STELLA), which is superior to the results of other standard single energy group hydrocodes such as VISPHOT or TITAN. Based on the results of our independent codes, we discuss the uncertainties involved in the current time-dependent models of supernova light curves.

Optical and near-infrared observations of SN 2011dh – The first 100 days

“…Shigeyama et al (1994) and Woosley et al (1994) used hydrodynamical modelling to show that a progenitor star with an initial mass of 12−15 M with an extended (not specified) but low mass (0.2−0.9 M ) hydrogen envelope reproduces the observed bolometric lightcurve. This was confirmed by the more detailed modelling of Blinnikov et al (1998). Progenitor observations were presented in Maund et al (2004) while Stancliffe & Eldridge (2009) used stellar evolutionary models to show that a progenitor star with an initial mass of 15-17 M with an extended but low mass hydrogen envelope, stripped through mass transfer to a companion star, reproduces the observed progenitor luminosity and effective temperature.…”

“…Tsvetkov et al (2009) used the hydrodynamical code STELLA (Blinnikov et al 1998) to show that a progenitor star with an initial mass of 13 M with an extended (600 R ) and low mass (not specified) hydrogen envelope well reproduces the UBVRI lightcurves except for the first few days.…”

A comparative study of Type II-P and II-L supernova rise times as exemplified by the case of LSQ13cuw

“…Suppressing the cooling/recombination wave results in a linearly declining light curve (Blinnikov & Bartunov 1993) and can be achieved if ejecta densities are sufficiently low (Grassberg et al 1971). A natural way of fulfilling this requirement is to reduce the hydrogen envelope mass to no more than a few solar masses as has been shown by several authors (Swartz et al 1991;Blinnikov & Bartunov 1993).…”

“…A natural way of fulfilling this requirement is to reduce the hydrogen envelope mass to no more than a few solar masses as has been shown by several authors (Swartz et al 1991;Blinnikov & Bartunov 1993). However, large progenitor radii are necessary in order to attain the brightness required by observed light curves.…”

“…During the early radiation-dominated phase, the luminosity is directly proportional to the progenitor radius (Swartz et al 1991;Blinnikov & Bartunov 1993). Thus, considering the shape and the total time of the rise to peak brightness for Type II-P and -L SNe, is a potentially fruitful endeavour.…”