Evidence for the emergence of stellar magnetic fields during rapid mass transfer
Abstract
Binary interaction fundamentally alters the evolution of massive stars, yet the physical consequences of mass transfer remain poorly constrained. Here we present high-resolution spectroscopic observations of Plaskett's Star (HD 47129) that reveal small radial-velocity variations of its magnetic secondary, coherent with the system's 14.4 d orbital period. These measurements support an evolved, post-mass-transfer configuration in which the narrow-lined primary is a partially Roche-lobe-filling stripped star with a mass of 5.9+1.8−1.4,M⊙, while the secondary is a 40.8+9.3−6.7,M⊙, rapidly rotating magnetic accretor. The system provides a rare opportunity to observe the immediate aftermath of mass transfer in a massive binary and offers compelling new evidence linking binary interaction to the emergence of strong stellar magnetism. Because magnetic fields regulate angular-momentum loss and transport, their formation through mass transfer could alter the subsequent evolution of massive binaries, with consequences for stellar populations, supernova progenitors and yields, and the formation of gravitational-wave sources.
Related
- Interaction of stellar dipole and disk magnetic fields in accretion-ejection systems
- Interaction of Stellar Dipole and Disk Magnetic Fields in Accretion–Ejection Systems
- Horizontal magnetic fields dominate the weak-field quiet Sun in Sunrise III observations. Evidence from traditional and transformer-based inversions
- Horizontal Magnetic Fields Dominate the Weak Field Quiet Sun in Sunrise III Observations. Evidence from Traditional and Transformer-Based Inversions
- Stellar proper motions compared with the plane-of-sky magnetic field
BibTeX
@misc{wade2026evidence,
title = {{Evidence for the emergence of stellar magnetic fields during rapid mass transfer}},
author = {Gregg A. Wade and Tomer Shenar and Pablo Marchant and Michael Abdul-Masih and Matteo Cantiello and Jason Grunhut and Oleg Kochukhov and Hugues Sana and Selma E. de Mink},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.25526},
eprint = {2609.25526},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.25526},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Evidence for the emergence of stellar magnetic fields during rapid mass transfer
AU - Gregg A. Wade
AU - Tomer Shenar
AU - Pablo Marchant
AU - Michael Abdul-Masih
AU - Matteo Cantiello
AU - Jason Grunhut
AU - Oleg Kochukhov
AU - Hugues Sana
AU - Selma E. de Mink
PY - 2026
DA - 2026/09/22
PB - arXiv
DO - 10.48550/arxiv.2609.25526
UR - https://arxiv.org/abs/2609.25526
AB - Binary interaction fundamentally alters the evolution of massive stars, yet the physical consequences of mass transfer remain poorly constrained. Here we present high-resolution spectroscopic observations of Plaskett's Star (HD 47129) that reveal small radial-velocity variations of its magnetic secondary, coherent with the system's 14.4 d orbital period. These measurements support an evolved, post-mass-transfer configuration in which the narrow-lined primary is a partially Roche-lobe-filling stripped star with a mass of 5.9^+1.8_−1.4,M_⊙, while the secondary is a 40.8^+9.3_−6.7,M_⊙, rapidly rotating magnetic accretor. The system provides a rare opportunity to observe the immediate aftermath of mass transfer in a massive binary and offers compelling new evidence linking binary interaction to the emergence of strong stellar magnetism. Because magnetic fields regulate angular-momentum loss and transport, their formation through mass transfer could alter the subsequent evolution of massive binaries, with consequences for stellar populations, supernova progenitors and yields, and the formation of gravitational-wave sources.
ER -