Parameterization of M Giants Based on WBVR and UGRIZ Photometric Data

The slope of the late-giant branch in some two-color diagrams differs considerably from the slope of other sequences as well as from the slope of reddening lines. This fact makes red giants an indispensable sourse of data on stellar parameters as well as on interstellar extinction. This study aims at finding two-color diagrams suitable for parameterization of M giants and developing techniques of parameterisation based on observed photometric data. As a result, we obtained an instrument for determination of intrinsic color indices, spectral types, and interstellar extinction for the $$WBVR$$ and $$ugriz$$ photometric systems. This paper is based, in part, on the talk presented at the “Modern Stellar Astronomy—2024” conference.