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Abstract: The unusual helium-rich type Ib supernova SN 2005E is distinguished fromany supernova hitherto observed by its faint and rapidly fading light curve,prominent calcium lines in late-phase spectra and lack of any mark of recentstar formation near the supernova location. These properties are claimed to beexplained by a helium detonation in a thin surface layer of an accreting whitedwarf Perets et al. 2010. Here we report on observations of SN 2005czappeared in an elliptical galaxy, whose observed properties resemble those ofSN 2005E in that it is helium-rich and unusually faint, fades rapidly, showsmuch weaker oxygen emission lines than those of calcium in the well-evolvedspectrum. We argue that these properties are best explained by a core-collapsesupernova at the low-mass end $8-12 M {\odot}$ of the range of massive starsthat explode Smartt 2009. Such a low mass progenitor had lost itshydrogen-rich envelope through binary interaction, having very thin oxygen-richand silicon-rich layers above the collapsing core, thus ejecting a very smallamount of radioactive $^{56}$Ni and oxygen. Although the host galaxy NGC 4589is an elliptical, some studies have revealed evidence of recent star-formationactivity Zhang et al. 2008, consistent with the core-collapse scenario.



Autor: K. S. Kawabata, K. Maeda, K. Nomoto, S. Taubenberger, M. Tanaka, J. Deng, E. Pian, T. Hattori, K. Itagaki

Fuente: https://arxiv.org/







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