2002/07/02 by Hideyuki Umeda, Ken'ichi Nomoto, Ken’ichi Nomoto +2 · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Gamma-ray bursts and supernovae #astro-ph
paper · pdf · doi:10.1086/342650
published as Astrophys.J. 578 (2002) 855-861 · 11 pages, 6 figures, To appear in the Astrophysical Journal 578, 2002
arxiv created 2002/07/02 · openalex publication_date 2002/10/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
X-ray observations have shown that the chemical abundance in the starburst galaxy M82 is quite rich in Si and S compared to oxygen. Such an abundance pattern cannot be explained with any combination of conventional Type I and II supernova yields. In addition, the energy-to-heavy-element mass ratio of the observed hot plasma is much higher than the value resulting from normal supernovae. We calculate abundances for explosive nucleosynthesis in core-collapse hypernovae and show that the abundance pattern and the large ratio between the energy and the heavy-element mass can be explained with hypernova nucleosynthesis. Such hypernova explosions are expected to occur for stars more massive than ≳20-25 M ☉ , and they likely dominate the starburst, because the time since the starburst in M82 is estimated to be as short as ~10 6 -10 7 yr. We also investigate pair-instability supernovae (~150-300 M ☉ ) and conclude that the energy-to-heavy-element mass ratio in these supernovae is too small to explain the observation.