Magnetic Archaeology of Early-Type Stellar Dynamos
arXiv:2110.03695 · doi:10.3847/1538-4357/ac2d2a
Abstract
Early-type stars show a bimodal distribution of magnetic field strengths, with some showing very strong fields () and others very weak fields (). Recently, we proposed that this reflects the processing or lackthereof of fossil fields by subsurface convection zones. Stars with weak fossil fields process these at the surface into even weaker dynamo-generated fields, while in stars with stronger fossil fields magnetism inhibits convection, allowing the fossil field to remain as-is. We now expand on this theory and explore the time-scales involved in the evolution of near-surface magnetic fields. We find that mass loss strips near-surface regions faster than magnetic fields can diffuse through them. As a result, observations of surface magnetism directly probe the frozen-in remains of the convective dynamo. This explains the slow evolution of magnetism in stars with very weak fields: these dynamo-\emph{generated} magnetic fields evolve on the time-scale of the mass loss, not that of the dynamo.
arXiv comment12 pages, 7 figures, accepted in ApJ
References in corpus (43)
- The NumPy array: a structure for efficient numerical computation
- Modules for Experiments in Stellar Astrophysics (MESA)
- Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
- Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
- Modules for Experiments in Stellar Astrophysics (MESA): Convective Boundaries, Element Diffusion, and Massive Star Explosions
- Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
- Mass-loss predictions for O and B stars as a function of metallicity
- Low Temperature Opacities
- Mass Loss: Its Effect on the Evolution and Fate of High-Mass Stars
- Dynamo action by differential rotation in a stably stratified stellar interior
- The evolution of rotating stars
- Shell-model calculations of stellar weak interaction rates: II. Weak rates for nuclei in the mass range A=45-65 in supernovae environment
- Mass loss from hot massive stars
- Updated Electron-Conduction Opacities: The Impact on Low-Mass Stellar Models
- Slowing the Spins of Stellar Cores
- Hydrodynamical Simulations of Corotating Interaction Regions and Discrete Absorption Components in Rotating O-Star Winds
- Dynamical Simulations of Magnetically Channeled Line-Driven Stellar Winds: II. The Effects of Field-Aligned Rotation
- Thermodynamic functions of dense plasmas: analytic approximations for astrophysical applications
- The MiMeS Survey of Magnetism in Massive Stars: Introduction and overview
- Predictions for mass-loss rates and terminal wind velocities of massive O-type stars
- Asteroseismology Can Reveal Strong Internal Magnetic Fields in Red Giant Stars
- Coulomb tunneling for fusion reactions in dense matter: Path integral Monte Carlo versus mean field
- Internal mixing of rotating stars inferred from dipole gravity modes
- Magnetic spots on hot massive stars
- New predictions for radiation-driven, steady-state mass-loss and wind-momentum from hot, massive stars II. A grid of O-type stars in the Galaxy and the Magellanic Clouds
- Mass loss in main-sequence B stars
- Magnetic massive stars as progenitors of "heavy" stellar-mass black holes
- Detection of a weak surface magnetic field on Sirius A: are all tepid stars magnetic ?
- The Magnetic Furnace: Intense Core Dynamos in B-stars
- The rapid rotation and complex magnetic field geometry of Vega
- Forward seismic modelling of the pulsating magnetic B-type star HD 43317
- Asteroseismic signatures of evolving internal stellar magnetic fields
- Detection of a magnetic field on HD108: clues to extreme magnetic braking and the Of?p phenomenon
- Modeling Ultraviolet Wind Line Variability in Massive Hot Stars
- On the Origin of Stochastic, Low-Frequency Photometric Variability in Massive Stars
- On magnetic inhibition of photospheric macro-turbulence generated in the iron-bump opacity zone of O-stars
- MOST detects corotating bright spots on the mid-O type giant ξ Persei
- Sirius A: turbulence or mass loss?
- A new weak-field magnetic DA white dwarf in the local 20 pc volume. The frequency of magnetic fields in DA stars
- Testing the fossil field hypothesis: could strongly magnetised OB stars produce all known magnetars?
- The interaction between shear and fingering (thermohaline) convection
- Multiple short-lived stellar prominences on O stars: The O6.5I(n)fp star lambda Cephei
- On the dynamical interaction between overshooting convection and an underlying dipole magnetic field -- I. The non-dynamo regime