Mass-loss Rates of 74 Bow Shock OB Stars: No Evidence for Bi-stability Behavior
Abstract
Accurate measurements of wind-driven mass-loss rates are essential for understanding the evolution and fate of massive stars. Established techniques for measuring Ṁ suffer from large dispersions and become insensitive in the regime of weak-winded late-O to early B stars. We employ a promising new technique to measure stellar mass loss for \numstars~early type stars that produce infrared stellar bow shock nebulae. We use updated stellar parameters, improved parallactic distances and proper motions, and modern dust models to characterize the bow shock nebulae and obtain new measurements of mass-loss rates. mdot ranges from 2×10−9 moperyear for weak-winded late-O and early B stars at log(lstar/L⊙)≈4.5 to 4×10−6 moperyear for the most luminous stars in our sample at log(lstar/L⊙)≈6.3. Stellar space velocities relative to their local standard of rest are insufficient to accurately reflect the relative star-ISM velocities for the majority of our sample, which have speeds much less than canonical runaway thresholds, suggesting the pervasive influence of bulk interstellar flows in forming bow shock nebulae. Adopting a minimum relative velocity of 20 kms is physically motivated and yields mass-loss rates in excellent agreement with the latest theoretical prescriptions while requiring no adjustable parameters. We find no enhancements in mdot for stars cooler than 25~kK, in agreement with modern mass-loss recipes that do not include bi-stability effects.
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BibTeX
@misc{patten2026massloss,
title = {{Mass-loss Rates of 74 Bow Shock OB Stars: No Evidence for Bi-stability Behavior}},
author = {Nikhil Patten and Henry A. Kobulnicky},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.24276},
eprint = {2610.24276},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.24276},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Mass-loss Rates of 74 Bow Shock OB Stars: No Evidence for Bi-stability Behavior
AU - Nikhil Patten
AU - Henry A. Kobulnicky
PY - 2026
DA - 2026/10/16
PB - arXiv
DO - 10.48550/arxiv.2610.24276
UR - https://arxiv.org/abs/2610.24276
AB - Accurate measurements of wind-driven mass-loss rates are essential for understanding the evolution and fate of massive stars. Established techniques for measuring Ṁ suffer from large dispersions and become insensitive in the regime of weak-winded late-O to early B stars. We employ a promising new technique to measure stellar mass loss for \numstars~early type stars that produce infrared stellar bow shock nebulae. We use updated stellar parameters, improved parallactic distances and proper motions, and modern dust models to characterize the bow shock nebulae and obtain new measurements of mass-loss rates. mdot ranges from 2×10^−9 moperyear for weak-winded late-O and early B stars at log(lstar/L_⊙)≈4.5 to 4×10^−6 moperyear for the most luminous stars in our sample at log(lstar/L_⊙)≈6.3. Stellar space velocities relative to their local standard of rest are insufficient to accurately reflect the relative star-ISM velocities for the majority of our sample, which have speeds much less than canonical runaway thresholds, suggesting the pervasive influence of bulk interstellar flows in forming bow shock nebulae. Adopting a minimum relative velocity of 20 kms is physically motivated and yields mass-loss rates in excellent agreement with the latest theoretical prescriptions while requiring no adjustable parameters. We find no enhancements in mdot for stars cooler than 25~kK, in agreement with modern mass-loss recipes that do not include bi-stability effects.
ER -