"Unusual Rainbow and White Rainbow" A new auroral candidate in oriental historical sources

TL;DR

This paper proposes that 'unusual rainbow' and 'white rainbow' terms in oriental historical sources may represent ancient auroras, expanding the scope of historical auroral records and aiding solar activity research.

Contribution

It introduces new terminology as potential auroral indicators in oriental historical texts and discusses their significance for historical solar activity studies.

Findings

'Unusual rainbow' and 'white rainbow' are plausible auroral candidates.

Inclusion of these terms can improve historical auroral catalogues.

Enhances understanding of historical solar activity records.

Abstract

Solar activity has been recorded as auroras or sunspots in various historical sources. These records are of much importance for investigating both long-term solar activities and extremely intense solar flares. In previous studies, they were recorded as "vapor," "cloud," or "light," especially in oriental historical sources; however, the terminology was not discussed adequately and is still quite vague. In this paper, we suggest the possibility of "unusual rainbow" and "white rainbow" as candidates of historical auroras in oriental historical sources and examine if it is probable. This discovery will help us to make more comprehensive historical auroral catalogues and require us to add these terms to auroral candidates in oriental historical sources.