Friday, 12 June 2009
A new type of stellar explosion
From Perets et al. (arXiv:0906.2003) Caption reads:
"Comparison of the SN 2005E ejecta mass and luminosity with other SNe [SNe Ia, squares;
SNe Ib/c, × marks; SNe II, circles]. The lower panel shows the total ejecta mass inferred for SN 2005E, which is the lowest inferred ejecta mass found for any SN, based on nebular spectra. Its position in the luminosity vs. ejecta-mass phase space is unique, suggesting it is not a member of currently well-known SN families. The middle panel shows the Ni mass inferred for SN 2005E. The small Ni mass inferred for SN 2005E is consistent with its low luminosity, although somewhat lower than might be expected from the extension of the observed Ni mass-luminosity relation observed for other SNe (dashed line and formula). The upper panel shows the Ni ejecta mass fraction MNi/Mtotal inferred for SN 2005E. The sources from which the SN data were collected are listed in the SI, Section 8."
This is a supernova that doesn't match any of the known classes. It was not found in a star forming region, so core collapse seems unlikely. It also ejected significantly less mass than any known SNIa. It has a very high Ca yield.