SEDust: A DUSTY-Based SED-Fitting Pipeline for Dust and Mass-Loss from AGB and LPV Stars
We present SEDust, an automated pipeline for spectral energy distribution (SED) fitting and the estimation of stellar mass-loss and dust-production rates. We apply this pipeline to quantify the mass-loss and dust injection rates in the dwarf galaxy NGC~6822, focusing on long-period variables (LPVs) and pulsating asymptotic giant branch (AGB) stars as major contributors to dust feedback into the interstellar medium. The total stellar mass-loss rate is found to be $(3.70 \pm 1.16) \times 10^{-3}\ M_{\odot} \mathrm{yr}^{-1}$. Two alternative methods (an LPV-based estimate and DESK) give totals that differ from this value by factors of $\sim$2.3 (lower) and $\sim$2.4 (higher), respectively, which we adopt as an estimate of the method-dependent systematic uncertainty. A positive correlation between stellar luminosity, intrinsic reddening caused by circumstellar dust self-extinction, and mass-loss rate is observed. The specific mass-return rate from AGB stars is $(7.40 \pm 2.30) \times 10^{-11}\ \mathrm{yr}^{-1}$, indicating that mass return from AGB stars alone is insufficient to sustain the current star formation rate of NGC~6822. This result implies the need for external gas accretion or additional mass-return mechanisms.