On the Origin of a Dusty Circumstellar Medium around Red Supergiants
Abstract
Red supergiant (RSG) stars are widely recognized as significant sources of dust, enriching the interstellar medium. However, the physical conditions that regulate dust nucleation in their winds remain poorly constrained. We investigate the formation of molecules and dust in RSG and explore how enhanced mass loss can produce a dense, dust-rich circumstellar medium (CSM) before core collapse. We couple time-dependent mass loss with non-equilibrium chemistry to model the formation of molecules and dust precursors using mass loss rates ranging from 10−6 to 10−2 \Mdot\ and both constant and accelerating wind profiles. Molecules such as CO, H2O, SiO, HCN, CS, SO, NH3, H2, and O2 form efficiently in the CSM, with masses varying between 10−15--10−2 \Ms. O-rich dust, namely silicates and alumina, dominates the dust composition. The total dust mass ranges between 10−8 and 3×10−3 \Ms. Accelerated winds produce more dust and allow dust formation closer to the stellar surface. The resulting fluxes exhibit strong mid-infrared excesses. The 9.7 and 18 \mic\ silicate features appear in either emission or absorption depending on the optical depth of the circumstellar medium. The time-dependent mass-loss history of our SN~2023ixf progenitor models results in a gradual increase in CSM dust mass toward explosion. A clumpy CSM provides a substantially better match to the observed optical and infrared fluxes, demonstrating the importance of time-dependent mass loss, CSM structure, and wind acceleration in shaping the observable properties of red supergiant progenitors.
Related
- Circumbinary discs as the origin of circumstellar material around interacting H-poor supernovae and fast blue optical transients
- The Molecular Circumstellar Environments of Red Supergiants in Galactic Open Clusters
- Properties of the circumstellar matter around the pair-instability supernova candidate SN 2018ibb revealed by its light curve
- Probing Feebly Interacting Particles with 511 keV Line from Circumstellar Medium of Supernovae
- A Parsec-scale Circumstellar Shell Around VX Sgr: Mass Loss and RSG/TŻO Nature
BibTeX
@misc{sujit2026origin,
title = {{On the Origin of a Dusty Circumstellar Medium around Red Supergiants}},
author = {Das Sujit and Arkaprabha Sarangi and Sutirtha Sengupta},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.28344},
eprint = {2608.28344},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.28344},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - On the Origin of a Dusty Circumstellar Medium around Red Supergiants
AU - Das Sujit
AU - Arkaprabha Sarangi
AU - Sutirtha Sengupta
PY - 2026
DA - 2026/08/28
PB - arXiv
DO - 10.48550/arxiv.2608.28344
UR - https://arxiv.org/abs/2608.28344
AB - Red supergiant (RSG) stars are widely recognized as significant sources of dust, enriching the interstellar medium. However, the physical conditions that regulate dust nucleation in their winds remain poorly constrained. We investigate the formation of molecules and dust in RSG and explore how enhanced mass loss can produce a dense, dust-rich circumstellar medium (CSM) before core collapse. We couple time-dependent mass loss with non-equilibrium chemistry to model the formation of molecules and dust precursors using mass loss rates ranging from 10^−6 to 10^−2 \Mdot\ and both constant and accelerating wind profiles. Molecules such as CO, H_2O, SiO, HCN, CS, SO, NH_3, H_2, and O_2 form efficiently in the CSM, with masses varying between 10^−15--10^−2 \Ms. O-rich dust, namely silicates and alumina, dominates the dust composition. The total dust mass ranges between 10^−8 and 3×10^−3 \Ms. Accelerated winds produce more dust and allow dust formation closer to the stellar surface. The resulting fluxes exhibit strong mid-infrared excesses. The 9.7 and 18 \mic\ silicate features appear in either emission or absorption depending on the optical depth of the circumstellar medium. The time-dependent mass-loss history of our SN~2023ixf progenitor models results in a gradual increase in CSM dust mass toward explosion. A clumpy CSM provides a substantially better match to the observed optical and infrared fluxes, demonstrating the importance of time-dependent mass loss, CSM structure, and wind acceleration in shaping the observable properties of red supergiant progenitors.
ER -