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 fitting approach to determine the dust-production rates (DPRs) and dust properties of the RSGs. We have fitted 4714 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 M _⊙ yr ^−1 –10 ^−7 M _⊙ yr ^−1 , and the total DPR of all RSGs is 1.14 ×10 ^−6 M _⊙ yr ^−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 $\mathrm{log}L/{L}_{\odot }\approx 4.4$ .

Keywords

• Red supergiant stars
• Stellar mass loss
• Circumstellar dust
• Large Magellanic Cloud
• Interstellar medium