Luminosity class of the symbiotic stars 4U1954+319 and ZZ CMi

Abstract

We performed optical photometry and spectral observations of the symbiotic stars 4U1954+319 and ZZ CMi. For 4U1954+319, using high-resolution spectra, we, measure the equivalent widths of diffuse interstellar bands (DIBs) and estimate the interstellar reddening E(B-V ) = 0:83?0:09. Using the GAIA distances and our photometry, we find: (1) the absolute V -band magnitude MV =-5:23 ? 0:08 of 4U1954+319 and that the mass donor is a supergiant of luminosity class Ib, and (2) MV = -0:27?0:2 for ZZ CMi and that the mass donor is a giant of luminosity class III.