Mass-loss Rate of Highly Evolved Stars in the Magellanic Clouds

TL;DR

This study analyzes the mass-loss rates of about 40,000 evolved stars in the Magellanic Clouds using spectral energy distribution fitting, revealing key relationships between stellar parameters and dust production, and providing a comprehensive catalog.

Contribution

It presents a new uniform catalog of evolved stars in the Magellanic Clouds with detailed stellar and dust properties, and investigates the relations between stellar parameters and mass-loss rates.

Findings

Total dust-production rate in LMC is approximately 9.69×10^{-6} M_sun/yr.

Total dust-production rate in SMC is approximately 1.75×10^{-6} M_sun/yr.

No significant difference in dust contribution between carbon-rich and oxygen-rich stars.

Abstract

Asymptotic giant branch stars (AGBs) and red supergiant stars (RSGs) exhibit significant mass loss phenomena and are considered important sources of interstellar dust. In this work, we employed an uniform method of spectral energy distribution fitting to analyze a large, and hence statistically significant, sample of approximately 40,000 RSGs and AGBs in the Magellanic Clouds (MCs), providing a new catalog of evolved stars that includes stellar parameters and dust properties. Our results reveal that the total dust-production rate (DPR) of the Large Magellanic Cloud is approximately $9.69\times10^{-6}\,\rm{M_{\odot }\, yr^{-1}}$, while it is around $1.75\times10^{-6}\,\rm{M_{\odot }\,yr^{-1}}$ for the Small Magellanic Cloud, with a few stars significantly contributing to the total DPR. No significant differences were observed in the contributions to DPR from carbon-rich and oxygen-rich (O-rich) evolved stars in the MCs. We explored the relations between stellar parameters (luminosity, infrared color, period, amplitude) and mass-loss rate (MLR) for evolved stars. A prominent turning point at $\log{(L/L_{\odot})} \approx 4.4$ appears in the luminosity-MLR diagram of RSGs, potentially related to the mass-loss mechanism of RSGs. The luminosity-MLR relation of AGBs is highly scattered. The DPR of AGBs shows a clear change with pulsation period and amplitude, with DPR exhibiting a drastic increase at pulsation periods of approximately 300 days and I-band amplitudes greater than 0.5 mag. Metallicity has some impact on the DPR of O-rich stars, with lower metallicity seeming to result in lower mean DPR and a higher proportion of optically thin stars.