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Fraser
2010-Feb-17, 08:00 PM
New results from the Chandra X-Ray Observatory suggests that the majority of Type 1a supernovae occur due to the merger of two white dwarfs. This new finding provides a major advance in understanding the type of supernova that astronomers use to measure the expansion of the Universe, which in turns allows astronomers to study [...]

More... (http://www.universetoday.com/2010/02/17/merging-white-dwarfs-set-off-supernovae/)

trinitree88
2010-Feb-17, 08:32 PM
New results from the Chandra X-Ray Observatory suggests that the majority of Type 1a supernovae occur due to the merger of two white dwarfs. This new finding provides a major advance in understanding the type of supernova that astronomers use to measure the expansion of the Universe, which in turns allows astronomers to study [...]

More... (http://www.universetoday.com/2010/02/17/merging-white-dwarfs-set-off-supernovae/)

Fraser. Big surprise. To his credit Bob Kirshner relented on his standard candle type 1a supernovae, giving a summary of a luminosity spread of at least a factor of three. SEE:http://arxiv.org/PS_cache/arxiv/pdf/0910/0910.0257v1.pdf According to WIKI, the mass of white dwarf progenitors runs from about half a solar mass, to the lower bound for type 2 core-collpse progenitors 8-10 solar masses. That's bound not only to cause the x ray variability predicted (and seen by Chandra), but some widespread magnitudes in the luminosity distribution. I'll bet a hot fudge sundae your putative dark energy disappears here, when they recalibrate all of their supernovae surveys by determining the spectral signatures of the ejecta. Some people like to sneak around near Christmas-time to see if they can figure out who is going to get what in a household...I always liked surprises. Surprise!
There are going to be a lot of people rehashing their data over this effect. It will be interesting to see how Jerry makes out on this. He has maintained for a long time that the distant population of Sne may be distinctly different from the local population and that will have to hold up after the dust settles.
As always in astronomy, like Mark Twain's New England weather..."If you don't like it, just wait a bit..." pete