Which information can we derive from historical Far Eastern guest stars for modern research on novae and cataclysmic variables?

TL;DR

This study re-examines historical Far Eastern records of guest stars to assess their potential as data points for understanding novae and cataclysmic variables, emphasizing the uncertainties in historical positions and the limitations for modern astrophysical conclusions.

Contribution

It critically evaluates the reliability of historical records for identifying modern binary systems and highlights the importance of astrophysical modeling over historical data alone.

Findings

Historical positions are often approximate or incorrect.

None of the historical counterparts can be definitively linked to known CVs.

Conclusions on binary evolution should rely on astrophysical observations and models.

Abstract

Recently, there have been several studies on the evolution of binary systems using historical data treated as facts in the chain of arguments. In this paper we discuss six case studies of modern dwarf novae with suggested historical counterpart from the historical point of view as well as the derived consequences for the physics of close binary systems (the dwarf novae Z Cam and AT Cnc, the nebula in M22, and the possible Nova 101, Nova 483, and Nova 1437). We consider the historical Far Eastern reports and after a careful re-reading of the text we map the given information on the sky. In some cases, the positions given in modern lists of classical nova-guest star-pairs turn out to be wrong, or they have to be considered highly approximate: The historical position, in most cases, should be transformed into areas at the celestial sphere and not into point coordinates. Based on the correct information we consider the consequences concerning the evolution of close binary systems. However, the result is that none of the cases of cataclysmic variables suggested to have a historical counterpart can be (fully) supported. As the identification of the historical record of observation with the CVs known today turns out to be always uncertain, a potential historical observation alone may not be relied on to draw conclusions on the evolution of binaries. The evolution scenarios should be derived from astrophysical observation and modelling only.