A new approach to generate a catalogue of potential historical novae

Abstract

Ancient Chinese, Korean, and Vietnamese observers left us records of celestial sightings, the so‐called “guest stars” dated up to ∼2500 years ago. Their identification with modern observable targets could open interesting insights into the long‐term behavior of astronomical objects, as shown by the successful identification of eight galactic supernovae. Here, we evaluate the possibility to identify ancient classical novae with presently known cataclysmic variables (CVs). For this purpose, we have developed a method which reconsiders in detail positions and sizes of ancient asterisms, in order to define areas on the sky that should be used for a search of modern counterparts. These areas range from a few to several 100 square degrees, depending on the details given in ancient texts; they should replace the single coordinate values given by previous authors. Any appropriate target (CVs, X‐ray binaries etc.) within these areas can be considered as a valid candidate for identification with the corresponding ancient event. Based on the original descriptions of several 100 old events, we selected those without movement and without a tail (to exclude comets) and which was not only visible within a certain hour (to exclude meteors). This way, we present a shortlist of 24 most promising events which could refer to classical nova eruptions. Our method is checked by applying it to the known SN identifications, leading to a margin of error between 0 and 4.5 degrees, meaning that some SN remnants lay exactly inside the areas given by the historical reports while in some other cases they are laying at considerable distances.

Simulated Sky

“…The analysis of historical astronomical records has become an important resource for research on long-term variability of stars (Fujiwara et al 2004;Fujiwara and Yamaoka 2005;Hamacher and Frew 2010;Hamacher 2018), comet orbits (Neuhäuser et al 2018), meteoritic events (Hamacher 2009), novae (Shara et al 2007;Duerbeck 2008;Patterson et al 2013;Miszalski et al 2016;Shara et al 2017), supernovae (Stephenson 1976;Clark and Stephenson 1977;Yau 1988;Stephenson and Green 2002;Green and Stephenson 2003;2017;Zhou et al 2018;Green 2019) and close interacting binary stars. Stellarium can be used to demonstrate transient phenomena like comets or "guest stars" recorded by historians and chroniclers (Zotti and Wolf 2020a;Hoffmann 2019b;Hoffmann et al 2020;Hoffmann and Vogt 2020a).…”

Bow shocks, nova shells, disc winds and tilted discs: the nova-like V341 Ara has it all

“…For comparison, Kepler's and Tycho's supernovae are thought to have reached m peak −3 and at m peak −4, respectively (Green & Stephenson 2003). We thus checked for positional coincidences in several compilations of historical guest star observations (Tse-Tsung 1957;Stephenson 1976Stephenson , 1971Clark & Stephenson 1976;Yang et al 2005;Stephenson & Green 2009;Hoffmann et al 2020). There were no matches closer than about 18 • , but we did uncover one potential counterpart: # 45 in Stephenson & Green (2009).…”

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

“…In this paper, we critically discuss recent publications Hoffmann et al 2020;Hoffmann & Vogt 2020a, 2020band 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. 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.…”