Ancient Greek observations of T Coronae Borealis? Data and methodologies

The “new star” which, according to Pliny the Elder, inspired Hipparchus to compile his star catalogue was not a comet and may have been the recurrent nova T Coronae Borealis. I first scrutinize Pliny’s sometimes over-interpreted report (surely based on a lost work by Hipparchus), then the evidence for Hipparchus’s dates. Data from Chinese annals, revised recently, point to a nova in the Libra–Scorpius region in 134 bc , probably too late in Hipparchus’s life to support Pliny’s claim. Likewise, the comet reported by Seneca and Justin, sometimes linked to this story, is now redated to 135 bc . After recalculating the interval between the 1866 and 1946 eruptions of T CrB, I confirm those posited for 1787 and 1217, using an English chronicle to refine the date of the latter. We know Hipparchus observed Corona Borealis; but the variation in intervals since ad 1217 rules out simple arithmetical reckoning of when T erupted during the 2nd century bc . More positive evidence comes from a suggestion that the naming of Coma Berenices in about 245 bc was inspired by an event in CrB. Given T’s roughly 80-year cycle, this suggests an eruption in the 160s, early in Hipparchus’s active life.