Spectra Of SN 1993J Research Articles

Modeling the X-ray emission of SN 1993J

Aims. We investigate the effects of radiative shocks on the observed X-ray emission from the type II supernova SN 1993J. To this end, the X-ray emission is modeled as a result of the interaction between the supernova ejecta and a dense circumstellar medium at an age of 8 years. Methods. The circumstances under which the reverse shock is radiative are discussed and the observed X-ray emission is analyzed using the numerical code described in Nymark et al. (2006, A&A, 449, 171). We argue that the original analysis of the X-ray observations suffered from the lack of self-consistent models for cooling shocks with high density and velocity, leading to questionable conclusions about the temperatures and elemental abundances. We reanalyze the spectra with our numerical model, and discuss the expected spectra for different explosion models for the progenitors. Results. We find that the spectra of SN 1993J are compatible with a CNO-enriched composition and that the X-ray flux is dominated by the reverse shock.

Detection of the Binary Companion to the Progenitor of SN 1993J

SummaryWe present a detailed late-time photometric and spectroscopic study of SN1993J with HST/ACS and Keck LRIS-B. We find a clear signature of a hot star component in the spectra of SN1993J which cannot be explained by the surrounding faint blue stars. This is the first detection of the expected massive binary companion to the red supergiant progenitor and confirms that SN1993J did indeed arise in an interacting binary system.

Fine Structures Appeared in the Spectrum of SN1993J

It was pointed out that Type Ⅱ supernovae would develop instabilities and asymmetric structure during its explosion. SN1987A, for the first time, provided direct and convincing observational evidence of such behavior. SN1993J confirmed this, too. On July 12, 1993, we obtained a low resolution (5.3 /pixel) spectrum of SN1993J using the 2.16 m telescope in Beijing Astronomical Observatory. We found that many fine structures appeared in the [OI] and H_x lines. This showed that clumping, chemical mixing and strong instabilities had occurred in the ejecta of

The nebular phase spectra of SN1993J

From June 19 to August 27, using the 2.16m telescope in the Beijing Astronomical Observatory, we obtained some low resolution spectra of SN1993J. The forbidden emission lines [O I], [Ca II] were very strong and dominated the spectra. However, the Hα and He lines were very weak. Many fine structures appeared in the Hα and [O I] lines. We found that the supernova had entered the nebular phase and strong instability and chemical mixing had occurred in the ejecta.

The ``Type IIb'' Supernova 1993J in M81: A Close Relative of Type Ib Supernovae

Spectra of SN 1993J at three epochs within the first 1.5 months after the explosion reveal the onset of a remarkable transformation. The prominent Hα emission line visible at early times became progressively weaker as P Cygni features of He I gradually appeared; SN 1993J is therefore a hydrogen-poor, helium-rich Type IIb supernova. The progenitor of SN 1993J was probably a reasonably massive star (initial mass 10-17 M ○. ) that transferred most, but not all, of its hydrogen envelope to a physically bound companion. We predict that many (≥6) months past maximum brightness, the spectrum of SN 1993J will closely resemble the late-time spectra of Type Ib supernovae; it will be dominated by strong emission lines of [O I], [Ca II], and Ca II, with Hα very weak or absent