The Great Comet of 1106, a Chinese Comet of 1138, and Daylight Comets in late 363 As Key Objects in Computer Simulated History of Kreutz Sungrazer System

We present the results of our orbital computations in support of the recently proposed contact-binary model for the Kreutz sungrazer system (Sekanina 2021, 2022). We demonstrate that comet Ikeya-Seki (C/1965 S1) previously passed perihelion decades after the Great Comet of 1106 (X/1106 C1) and argue that, like the Great September Comet of 1882 (C/1882 R1), it evidently was a fragment of the comet recorded by the Chinese in September 1138. The 1106 sungrazer appears instead to have been the previous appearance of the Great March Comet of 1843 (C/1843 D1). With no momentum exchange involved, fragments of a Kreutz sungrazer breaking up tidally near perihelion are shown to end up in orbits with markedly different periods because their centers of mass are radially shifted by a few kilometers relative to the parent. The daylight comets of AD 363, recorded by a Roman historian, are accommodated in our computations as the first appearance of the Kreutz sungrazers after their bilobed progenitor's breakup. We link the 1843-1106-363 (Lobe I) and 1882-1138-363 (Lobe II) returns to perihelion by single nongravitational orbits and gravitationally with minor center-of-mass shifts acquired in fragmentation events. We also successfully model the motion of Aristotle's comet as the rotating progenitor that at aphelion split (at a few m/s) into the two lobes, the precursors of, respectively, the 1843 and 1882 sungrazers; and provide a 1963-1041-363 link for comet Pereyra (C/1963 R1). Material fatigue could contribute to sungrazers' fragmentation throughout the orbit, including aphelion. -- Continuing problems with the nongravitational law in orbit software are noted.