Determining the magnitudes and spectral types of the components of the binary Mira X Ophiuchi

TL;DR

This study refines the magnitudes and spectral types of the binary Mira X Ophiuchi's components using new photometric and spectroscopic data from 2016, revealing variability in the Mira component and a stable constant star.

Contribution

It provides updated and precise measurements of the magnitudes and spectral types of both components based on recent observations, improving previous estimates.

Findings

Constant star has V magnitude 9.0 and spectral type K1III.

Mira's spectral type varies from M6III to M7III.

Mira's V magnitude varies from 6.47 to 9.83.

Abstract

Several values for the magnitudes and spectral types of the components of the binary Mira X Ophiuchi have been published in the literature over the last century. Analysis of new photometry and spectroscopy of the star between 2016 May and 2016 December indicates that the V magnitude of the constant star is 9.0 and its spectral type K1III. The spectral type of the Mira changed from M6III at maximum to M7III as it faded and passed through minimum. The V magnitude of the Mira varied between 6.47 at maximum and 9.83 at minimum, a range of 3.36 magnitudes.