The World's Strangest Supernova May Not Be a Supernova At All (Abstract)

Volume 40 number 1 (2012)

Caroline Moore

29 Deer Pond Drive, Warwick, NY 10990; caroline.moore@deer-pond-observatory.com

Abstract

(Abstract only) SN 2008ha is the least luminous supernova ever to be observed. It is unclear what caused this obscurity to occur. For the last three years I have been doing independent follow-up research on SN 2008ha. SN 2008ha is believed to be 100 times brighter than a nova, but 1,000 times dimmer then a supernova. The spectrum to some degree was classic Type Ia supernova because of the lack of hydrogen and abundance of silicon, but there are many other factors to be considered. SN 2008ha had a short rise time of only 10 days (typical Type Ia is 19.5 days). It has low expansion velocities of only 2,000km compared to the typical Ia with very small kinetic energy per unit mass of ejecta. Although some elements of the spectrum are consistent with those of a Type Ia, narrow lines were observed. This is just one of several characteristics that SN 2008ha shares with the “SN 2002cx-like class” of supernovae. SN 2008ha is believed to be the most extreme of this sub-class of supernovae with the smallest amount of space between lines, 5 days shorter rise time, being significantly fainter, and having lower velocities. With all these things considered, it does make classification as a Type Ia questionable. In fact it is even questionable if this is a supernova at all, and not just an “imposter.” This may have just been a “star burp” which means that the supernova may have failed, resulting in some parts of the star being left, maybe even enough remains to explode again as seen in the case of SN 2006jc. This may have occurred because the explosion was not deep enough in the core of the star, and only eliminating some or all of the hydrogen envelope and leaving behind the carbon and oxygen inner layers, instead resulting in a Type Ic supernova. It would be interesting to see what, if anything is left of the star; this could make it a possible Hubble candidate. The idea that it may “burp” again makes it especially important.