Weak magnetic fields in early-type stars: failed fossils
arXiv:1201.5646 · doi:10.1093/mnras/sts109
Abstract
Weak magnetic fields have recently been detected in Vega and Sirius. Here, we explore the possibility that these fields are the remnants of some field inherited or created during or shortly after star formation and, unlike true fossil fields, are still evolving as we observe them. The timescale of this evolution is given in terms of the Alfven timescale and the rotation frequency by tau_evol ~ tau_A^2 Omega, which would be comparable to the age of the star. It is shown that it is likely that all intermediate- and high-mass stars contain fields of at least the order of the strength found so far in Vega and Sirius. Faster rotators are expected to have stronger magnetic fields. Stars may experience an increase in field strength during their early main-sequence, but for most of their lives field strength will decrease slowly. The length scale of the magnetic structure on the surface may be small in very young stars but should quickly increase to at least very approximately a fifth of the stellar radius.
are welcome. Submitted to MNRAS. Five pages
References in corpus (6)
- Weak magnetic fields in Ap/Bp stars: Evidence for a dipole field lower limit and a tentative interpretation of the magnetic dichotomy
- Magnetic spots on hot massive stars
- On non-axisymmetric magnetic equilibria in stars
- Detection of a weak surface magnetic field on Sirius A: are all tepid stars magnetic ?
- Magnetic Activity in Stellar Merger Products
- On the magnetic flux problem in star formation
Cited by in corpus (34)
- A Volume Limited Survey of mCP Stars Within 100pc II: Rotational and Magnetic Properties
- Asteroseismic signatures of evolving internal stellar magnetic fields
- Envelope Convection, Surface Magnetism and Spots in A- and late B-type Stars
- A Volume-Limited Survey of mCP Stars Within 100pc I: Fundamental Parameters and Chemical Abundances
- Magnetic Field Generation in Stars
- MOBSTER - II. Identification of rotationally variable A stars observed with \emph{TESS} in Sectors 1 to 4
- Detection of ultra-weak magnetic fields in Am stars: beta UMa and theta Leo
- Period spacings of gravity modes in rapidly rotating magnetic stars I. Axisymmetric fossil field with poloidal and toroidal components
- Magnetic grain trapping and the hot excesses around early-type stars
- Discovery of a very weak magnetic field on the Am star Alhena
- Discovery of starspots on Vega - First spectroscopic detection of surface structures on a normal A-type star
- Detecting axisymmetric magnetic fields using gravity modes in intermediate-mass stars
- Magnetic fields driven by tidal mixing in radiative stars
- Fossil field decay due to nonlinear tides in massive binaries
- Detectability of small-scale magnetic fields in early-type stars
- Magnetic geometry and surface differential rotation of the bright Am star Alhena A
- Detecting deep axisymmetric toroidal magnetic fields in stars. The traditional approximation of rotation for differentially rotating deep spherical shells with a general azimuthal magnetic field
- Burn Out or Fade Away? On the X-ray and Magnetic Death of Intermediate Mass Stars
- The dichotomy between strong and ultra-weak magnetic fields among intermediate-mass stars
- MOBSTER -- III. HD 62658: a magnetic Bp star in an eclipsing binary with a non-magnetic 'identical twin'
- Spot distribution and fast surface evolution on Vega
- Magnetic fields in late-stage proto-neutron stars
- A decade of radial-velocity monitoring of Vega and new limits on the presence of planets
- Rotational modulation in A and F stars: Magnetic stellar spots or convective core rotation?
- A search for weak or complex magnetic fields in the the B3V star iota Herculis
- Magnetic chemically peculiar stars investigated by the Solar Mass Ejection Imager
- gamma Peg: testing Vega-like magnetic fields in B stars
- A decade-long magnetic monitoring of Vega
- Magnetic fields in O-, B- and A-type stars on the main sequence
- Rotational modulation and single g-mode pulsation in the B9pSi star HD174356?
- Magnetic Fields or Overstable Convective Modes in HR 7495: Exploring the Underlying Causes of the Spike in the 'Hump & Spike' Features
- Secular dipole-dipole stability of magnetic binaries
- The nature and origin of magnetic fields in early-type stars
- Stable magnetic fields and changing starspots on Vega -- An ultra-deep decadal survey at Pic du Midi and OHP