Infrared characteristics of the BIS catalog objects

TL;DR

This study analyzes infrared color-color diagrams of 276 BIS catalog stars, using spectroscopy and infrared data to classify stars and identify their variability and chemical types, revealing the absence of dusty Carbon stars and the presence of Miras and early M types.

Contribution

It introduces a new infrared color diagram method combining 2MASS, AKARI, and WISE data for star classification and variability discrimination in the BIS catalog.

Findings

WISE 3.4-12 vs 12-22 plot effectively discriminates variability types.

2MASS-AKARI diagram distinguishes Carbon and Mira stars.

No dusty Carbon stars are present in the BIS catalog.

Abstract

We have studied several color-color infrared diagrams of the 276 late type stars of the BIS catalog. For 95 of these stars we derived spectral classification from our slit spectroscopy. From the 2MASS color diagram we derive that none of the sample stars is a dwarf. The WISE 3.4-12 vs 12-22 plot is the best to discriminate the variability type (Mira, irregular and not-variable), as well as Carbon stars: IRAS colors are less useful due to the poor quality of the data for most of the BIS stars. Mixed plots involving 2MASS, AKARI and WISE were also explored: the 2MASS-AKARI J-[S09] vs [S09]-[L18] plot is efficient to discriminate Carbon and Mira stars. From the color plots and our spectroscopy we can statistically predict that in whole BIS catalog no other dusty Carbon star is present, while a few Miras and CH or R Carbon stars could be discovered. Only about 15 percent of the BIS stars are of early M type.