On the Luminosity and Mass Loss of Galactic AGB Stars

TL;DR

This study reanalyzes Galactic AGB stars, focusing on their luminosity and mass loss, using infrared data to improve bolometric magnitude estimates and address the luminosity problem in carbon-rich stars.

Contribution

It provides a detailed infrared analysis of AGB stars, demonstrating the importance of mid-IR fluxes for accurate luminosity and mass-loss rate estimations, and resolves the luminosity discrepancy in C stars.

Findings

Mid-IR fluxes are essential for accurate bolometric magnitudes.

The luminosity problem of C stars is not supported by the data.

Reliable mass-loss rates can be derived from IR observations.

Abstract

As part of a reanalysis of Galactic Asymptotic Giant Branch stars (hereafter AGB stars) at infrared wavelengths, we discuss here two samples (the first of carbon-rich stars, the second of S stars) for which photometry in the near- and mid-IR and distance estimates are available. Whenever possible we searched also for mass-loss rates. The observed spectral energy distributions extended in all cases up to 20 $\mu$m and for the best-observed sources up to 45 $\mu$m. The wide wavelength coverage allows us to obtain reliable bolometric corrections, and hence bolometric magnitudes. We show that mid-IR fluxes are crucial for estimating bolometric magnitudes for stars with dusty envelopes and that the so-called luminosity problem of C stars (i.e. the suggestion that they are less luminous than predicted by models) does not appear to exist.