The Extreme Scarcity of Dust-enshrouded Red Supergiants: Consequences for Producing Stripped Stars via Winds

被引:16
|
作者
Beasor, Emma R. [1 ]
Smith, Nathan [2 ]
机构
[1] NSFs NOIRLab, 950 N Cherry Ave, Tucson, AZ 85719 USA
[2] Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721 USA
来源
ASTROPHYSICAL JOURNAL | 2022年 / 933卷 / 01期
关键词
MASS-LOSS RATES; EFFECTIVE TEMPERATURE SCALE; LARGE-MAGELLANIC-CLOUD; COOL SUPERGIANTS; MILKY-WAY; EVOLUTION; EMISSION; SUPERNOVA; SINGLE; PROGENITORS;
D O I
10.3847/1538-4357/ac6dcf
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Quiescent mass loss during the red supergiant (RSG) phase has been shown to be far lower than prescriptions typically employed in single-star evolutionary models. Importantly, RSG winds are too weak to drive the production of Wolf-Rayet (WR) stars and stripped-envelope supernovae (SE-SNe) at initial masses of roughly 20-40 M-circle dot. If single stars are to make WR stars and SE-SNe, this shifts the burden of mass loss to rare dust-enshrouded RSGs (DE-RSGs), objects claimed to represent a short-lived, high-mass-loss phase. Here, we take a fresh look at the purported DE-RSGs. By modeling the mid-IR excesses of the full sample of RSGs in the Large Magellanic Cloud, we find that only one RSG has both a high mass-loss rate ((M) over dot >= 10(-4) M-circle dot yr(-1)) and a high optical circumstellar dust extinction (7.92 mag). This RSG is WOH G64, and it is the only one of the 14 originally proposed DE-RSGs that is actually dust enshrouded. The rest appear to be either normal RSGs without strong IR excess, or lower-mass asymptotic giant branch stars. Only one additional object in the full catalog of RSGs (not previously identified as a DE-RSG) shows strong mid-IR excess. We conclude that if DE-RSGs do represent a pre-SN phase of enhanced M in single stars, it is extremely short-lived, only capable of removing <= 2 M-circle dot of material. This rules out the single-star post-RSG pathway for the production of WR stars, luminous blue variables, and SE-SNe. Single-star models should not employ M-prescriptions based on these extreme objects for any significant fraction of the RSG phase.
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页数:14
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