Sonett suggests that a single supernova would produce two or three shock waves, an initial forward shock and a pair of reverse shocks from the initial expansion and a reflected wave from the shell boundary of a more ancient supernova.39,40 Fig. 2 shows that each episode in a series produced a similar amount of atmospheric radiocarbon. The sun lies almost exactly in the center41 of the Local Bubble, believed to be the result of a past nearby supernova event. A candidate for the reverse shock wave is the supernova remnant North Polar Spur, with an estimated age of 75,000 years and a distance of 130 ± 75 parsecs (424 light years),42 conveniently located in the north sky from where it would have preferentially irradiated the Northern Hemisphere. Assuming the Taylor flux is average and 1,000 neutrons are produced per erg of gamma-ray energy,43 the catastrophe would have released about 1016 erg/cm2 (2 x 108 cal/cm2), corresponding to a solar flare of 1043 ergs or a gamma-flash of 1054 ergs from a supernova about 1 parsec away.
S.C.--And what is the status of Betelgeuse? Variable currently low light phase? Or supernova possible/pending? (Maybe we should worry about it after the 1 mile asteroid this weekend!)
Whatever you do, don't say the name three times! :^)
the Local Bubble
That'll make a good topic for the near future, I think; meanwhile, it reminds me, I've still got TSLA shares, I'm still making money like Capone, and need to pick up some antacids.