Long-period Variable Stars in NGC 147 and NGC 185. II. Their Dust Production

Abstract This study presents a comparative analysis of mass-loss and dust production rates in the dwarf galaxies NGC 147 and NGC 185, focusing on long-period variables (LPVs) and pulsating asymptotic giant branch stars as primary indicators of dust feedback into the interstellar medium. For NGC 147, the total mass-loss rate is calculated as (9.44 ± 3.78) × 10 −4 M ⊙ yr −1 , with LPV luminosities ranging from (6.20 ± 0.25) × 10 2 L ⊙ to (7.87 ± 0.32) × 10 3 L ⊙ . In NGC 185, the total mass-loss rate is higher, at (1.58 ± 0.63) × 10 −3 M ⊙ yr −1 , with LPV luminosities spanning (5.68 ± 0.23) × 10 2 L ⊙ to (1.54 ± 0.66) × 10 4 L ⊙ . A positive correlation is observed between stellar luminosity, intrinsic reddening due to circumstellar dust self-extinction, and elevated mass-loss rates. Additionally, comparisons of calculated dust injection rates, two-dimensional dust distribution maps, and observed dust masses provide evidence for a gravitational interaction between NGC 147 and the Andromeda galaxy, which influences the dust distribution within the system.