Oxygen rich cool stars in the Cepheus region, New observations. III

TL;DR

This study presents new spectral and photometric observations of seven oxygen-rich cool stars in Cepheus, revises their classifications, and analyzes their variability and distances using light curves and period-luminosity relations.

Contribution

It provides updated spectral classifications and variability analysis for seven stars, including the identification of semi-regular and Mira variables, with distance estimates based on period-luminosity relations.

Findings

Revised spectral classifications for the seven stars.

Identification of KP2001-18 as semi-regular and KP2001-176 as Mira variables.

Estimated distances to the variable stars using period-luminosity relations.

Abstract

We present moderate resolution CCD spectra and R photometry for seven KP2001 stars. We revised the spectral classification of the stars in the range 3900 - 8500 A. On the bases of light curves of the NSVS (Northern Sky Variability Survey) database we classify KP2001-18 as a semi regular and KP2001-176 as Mira type variables. For all observed objects NSVS phase - dependence light curve analysis and variability type classification was performed with the VStar Software. Using period luminosity relation we computed MK magnitudes and the distances to variables.