Counterparts of Far Eastern Guest Stars: Novae, supernovae, or something else?

Abstract

Historical observations of transients are crucial for studies of their long-term evolution. This paper forms part of a series of papers in which we develop methods for the analysis of ancient data of transient events and their usability in modern science. Prior research on this subject by other authors has focused on looking for historical supernovae and our earlier work focused on cataclysmic binaries as classical novae. In this study we consider planetary nebulae, symbiotic stars, supernova remnants, and pulsars in the search fields of our test sample. We present the possibilities for these object types to flare up visually, give a global overview on their distribution, and discuss the objects in our search fields individually. To summarize our results, we provide a table of the most likely identifications of the historical sightings in our test sample and outline our method in order to apply it to further historical records in future works. Highlights of our results include a re-interpretation of two separate sightings as one supernova observation from May 667 to June 668 CE, the remnant of which could possibly be SNR G160.9+02.6. We also suggest the recurrent nova U Sco as a candidate for the appearance observed between Scorpius and Ophiuchus in 891, which could point towards a long-term variability of eruption amplitudes. In addition, we find that the ‘shiny bright’ sighting in 1431 can be linked to the symbiotic binary KT Eri, which erupted as a naked eye classical nova in 2009.

Critical comments on publications by S. Hoffmann and N. Vogt on historical novae/supernovae and their candidates

“…This is presented here. In Section 2, we discuss the first two papers on previous historical SNe and novae (Hoffmann 2019; Vogt et al 2019), in Section 3 additional papers on their nova suggestions (Hoffmann et al 2020;Hoffmann & Vogt 2020a, 2020b, and in Section 4 we finish with a summary and final remarks. 1 Neuhäuser et al (2021a) have shown in detail that the sources used for two of the highlights in Hoffmann and Vogt (2020b), namely a presumable new historical SN AD 1 The papers by Vogt et al (2019), ), Hoffmann et al (2020, and Vogt (2020a, 2020b) were submitted without the consent of RN and after the participation of SH in the project had been terminated in a mutual agreement between RN and SH in February 2019.…”

“…Neuhäuser et al 2021b). In this article, we deal with suggested historical novae and SNe (Hoffmann et al 2020; Hoffmann & Vogt 2020a, 2020b)—however, many of their candidates are not star‐like, but obviously comets.…”

“…In this paper, we critically discuss recent publications (Hoffmann 2019; Hoffmann et al 2020; Hoffmann & Vogt 2020a, 2020b and Vogt et al 2019) on historical East Asian guest stars, where they mainly aimed at identifying nova candidates. However, as we will show, there are many strong shortcomings in their work.…”

“…This is presented here. In Section 2, we discuss the first two papers on previous historical SNe and novae (Hoffmann 2019; Vogt et al 2019), in Section 3 additional papers on their nova suggestions (Hoffmann et al 2020; Hoffmann & Vogt 2020a, 2020b), and in Section 4 we finish with a summary and final remarks.…”

“…Neuhäuser et al (2021a) have shown in detail that the sources used for two of the highlights in Hoffmann and Vogt (2020b), namely a presumable new historical SN AD 667‐8 and a recurrent nova in AD 891, both obviously pertain to known comets.…”