86 GHz SiO maser survey of late-type stars in the Inner Galaxy III. Interstellar extinction and colours of the SiO targets

TL;DR

This study determines interstellar extinction corrections for late-type stars in the Inner Galaxy, analyzes their infrared properties, and estimates their mass-loss rates, enhancing understanding of stellar evolution in dense galactic regions.

Contribution

It provides a new measurement of the near-infrared extinction law and derives mass-loss rates for SiO maser target stars in the Inner Galaxy.

Findings

Extinction law approximated by A$_b4 \\propto \\lambda^{-1.9 \\pm 0.1}

Mass-loss rates between 10^{-7} and 10^{-5} M$_\odot$ yr$^{-1}$

Infrared properties of Mira stars reviewed

Abstract

We have determined extinction corrections for a sample of 441 late-type stars in the inner Galaxy, which we previously searched for SiO maser emission, using the 2MASS near-infrared photometry of the surrounding stars. From this, the near-infrared extinction law is found to be approximated by a power law A$_\lambda \propto \lambda^{-1.9\pm0.1}$. Near- and mid-infrared colour-colour properties of known Mira stars are reviewed. From the distribution of the dereddened infrared colours of the SiO target stars we infer mass-loss rates between $10^{-7}$ and $10^{-5}$ M$_\odot$ yr$^{-1}$.