Kreutz Sungrazers: Summary of Recent Modeling and Orbits of the SOHO Objects

Abstract

I summarize and streamline the results of recent modeling of the orbital evolution and cascading fragmentation of the Kreutz sungrazers. The model starts with Aristotle's comet -- the progenitor whose nucleus is assumed to be a contact binary -- splitting near aphelion into the two lobes and concludes with the SOHO dwarf objects as the end products of the fragmentation process. The Great March Comet of 1843, a member of Population I, and the Great September Comet of 1882, a member of Population II, are deemed the largest surviving masses of the lobes. I establish that the Kreutz system consists currently of nine populations, one of which -- associated with comet Pereyra -- is a side branch of Population I. The additions to the Kreutz system proposed as part of the new model are the daylight comets of AD 363, recorded by the Roman historian Ammianus Marcellinus, and the Chinese comets of September 1041 and September 1138, both listed in Ho's catalogue. The comets of 363 are the first-generation fragments, the latter -- together with the Great Comet of 1106 -- the second-generation fragments. Attention is directed toward the populations' histograms of perihelion distance of the SOHO sungrazers and the plots of this distance as a function of the longitude of the ascending node. Arrival of bright, naked-eye Kreutz sungrazers in the coming decades is predicted.