1998/07/31 by P. Hoêflich, P. Hoeflich, Hoeflich, P. +4
Physics and Astronomy · #Astro and Planetary Science #Astrophysics (astro-ph) #FOS: Physical sciences #Gamma-ray bursts and supernovae #Nuclear Physics and Applications #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9807345
5 pages, 2 figures, submitted to ApJ Letters
arxiv created 1998/07/31 · openalex publication_date 1998/07/31 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The recent discovery of the unusual supernova SN1998bw and its apparent correlation with the gamma-ray burst GRB 980425 has raised new issues concerning both the GRB and SNe. SN1998bw was unusually bright at maximum light and expansion velocities were large making SN1998bw a possible candidate for a "hypernova" with explosion energies exceeding 1052 erg. We show that the light curve of SN1998bw can be understood as the result of an aspherical explosion along the rotational axis of a basically spherical, non-degenerate C/O core of a massive star with an explosion energy of 2E51 erg, a total ejecta mass of 2 Mo, and a 56Ni mass of 0.2Mo if it is seen from high inclinations with respect to the plane of symmetry.In this model, the high expansion velocities are a direct consequence of the aspherical explosion which, in turn, produces oblate iso-density contours. This suggests that the fundamental core-collapse explosion process itself is strongly asymmetric.