AGB candidates in the field of gamma Cas

TL;DR

This study monitored 530 candidate AGB stars using spectroscopy and photometry, identifying various types and analyzing their properties, including spectral types, variability, and distances, with some comparison to Gaia data.

Contribution

It provides a comprehensive classification and analysis of AGB candidates, combining historical light curves, spectral data, and modern catalogs to enhance understanding of their properties.

Findings

Identified 10 Miras, 5 stars with long-term trends, 3 semiregular, and 3 irregular variables.

Spectral types included 8 M-type, 7 C-type, and 6 S-type stars.

Median distance of Mira stars estimated at 4.9 kpc, with comparison to Gaia parallaxes discussed.

Abstract

We report the spectroscopic and photometric monitoring of a sample of 530 candidate AGB stars in a 5 degrees field, selected from the IPHAS catalog: historic light curves were derived from Asiago IR plates taken in the years 1965 -1984. We found 10 Miras, 5 stars with long term trends, 3 semiregular and 3 irregular. Spectral types from CCD slit spectra gave 8 M-type, 7 C-type and 6 S-type stars. In the color-color plots made from IPHAS and 2MASS catalogs, the S-type and M-type stars occupy the same regions, while C-type stars are well separated. All C-type stars with IR excess showed long term trends in their light curve. Distances of the Mira stars, estimated from their periods and K magnitudes, gave a median value of 4.9 kpc with a large spread. A comparison with astrometric parallaxes from Gaia DR2 is briefly discussed.