Evolved Massive Stars at Low-metallicity VI. Mass-Loss Rate of Red Supergiant Stars in the Large Magellanic Cloud

Abstract

Mass loss is a crucial process that affects the observational properties, evolution path and fate of highly evolved stars. However, the mechanism of mass loss is still unclear, and the mass-loss rate (MLR) of red supergiant stars (RSGs) requires further research and precise evaluation. To address this, we utilized an updated and complete sample of RSGs in the Large Magellanic Cloud (LMC) and employed the 2-DUST radiation transfer model and spectral energy distribution (SED) fitting approach to determine the dust-production rates (DPRs) and dust properties of the RSGs. We have fitted 4,714 selected RSGs with over 100,000 theoretical templates of evolved stars. Our results show that the DPR range of RSGs in the LMC is $10^{-11}{\mathrm{M}}_{\odot }\mathrm{y}{\mathrm{r}}^{-1}$ to $10^{-7}{\mathrm{M}}_{\odot }\mathrm{y}{\mathrm{r}}^{-1}$, and the total DPR of all RSGs is 1.14 $\times 10^{-6}{\mathrm{M}}_{\odot }\mathrm{y}{\mathrm{r}}^{-1}$. We find that $63.3\%$ RSGs are oxygen-rich, and they account for $97.2\%$ of the total DPR. The optically thin RSG, which comprise $30.6\%$ of our sample, contribute only $0.1\%$ of the total DPR, while carbon-rich RSGs ($6.1\%$) produce $2.7\%$ of the total DPR. Overall, 208 RSGs contributed $76.6\%$ of the total DPR. We have established a new relationship between the MLR and luminosity of RSGs in the LMC, which exhibits a positive trend and a clear turning point at $\log L/L_{\odot }\approx 4.4$.

Accepted for publication in AJ