Observations of Cool-Star Magnetic Fields
arXiv:1203.0241 · doi:10.12942/lrsp-2012-1
Abstract
Cool stars like the Sun harbor convection zones capable of producing substantial surface magnetic fields leading to stellar magnetic activity. The influence of stellar parameters like rotation, radius, and age on cool-star magnetism, and the importance of the shear layer between a radiative core and the convective envelope for the generation of magnetic fields are keys for our understanding of low-mass stellar dynamos, the solar dynamo, and also for other large-scale and planetary dynamos. Our observational picture of cool-star magnetic fields has improved tremendously over the last years. Sophisticated methods were developed to search for the subtle effects of magnetism, which are difficult to detect particularly in cool stars. With an emphasis on the assumptions and capabilities of modern methods used to measure magnetism in cool stars, I review the different techniques available for magnetic field measurements. I collect the analyses on cool-star magnetic fields and try to compare results from different methods, and I review empirical evidence that led to our current picture of magnetic fields and their generation in cool stars and brown dwarfs.
Published version at http://www.livingreviews.org/lrsp-2012-1
References in corpus (18)
- Constraining the Age-Activity Relation for Cool Stars: The SDSS DR5 Low-Mass Star Spectroscopic Sample
- A Substantial Amount of Hidden Magnetic Energy in the Quiet Sun
- The First Direct Measurements of Magnetic Fields on Very Low-Mass Stars
- Chromospheric Activity, Rotation, and Rotational Braking in M and L Dwarfs
- Confirmation of the Electron Cyclotron Maser Instability as the Dominant Source of Radio Emission from Very Low Mass Stars and Brown Dwarfs
- The large-scale axisymmetric magnetic topology of avery-low-mass fully-convective star
- A catalogue of rotation and activity in early-M stars
- The large-scale magnetic field and poleward mass accretion of the classical T Tauri star TW Hya
- M-dwarf metallicities - A high-resolution spectroscopic study in the near infrared
- The close classical T Tauri binary V4046 Sgr: Complex magnetic fields & distributed mass accretion
- Magnetic-field measurements of T Tauri stars in the Orion Nebula cluster
- The Narrowest M-dwarf Line Profiles and the Rotation-Activity Connection at Very Slow Rotation
- Spectropolarimetry of the Classical T Tauri Star TW Hydrae
- HD 46375: seismic and spectropolarimetric analysis of a young Sun hosting a Saturn-like planet
- The first magnetic maps of a pre-main sequence binary star system - HD 155555
- Magnetic fields in M dwarfs: rapid magnetic field variability in EV Lac
- Rapid magnetic flux variability on the flare star CN Leonis
- Magnetospheric Accretion in Classical T Tauri Stars
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- ACCESS I: An Optical Transmission Spectrum of GJ 1214b Reveals a Heterogeneous Stellar Photosphere
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- Strong dipole magnetic fields in fast rotating fully convective stars
- Auroral radio emission from late L and T dwarfs: A new constraint on dynamo theory in the substellar regime
- The evolution of the solar wind
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- The Sun is less active than other solar-like stars
- The Starspots of HAT-P-11: Evidence for a Solar-like Dynamo
- Magnetic Inhibition of Convection and the Fundamental Properties of Low-Mass Stars. II. Fully Convective Main Sequence Stars
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- A basal contribution from p-modes to the Alfvénic wave flux in the Sun's corona
- Investigating the young AU~Mic system with SPIRou: large-scale stellar magnetic field and close-in planet mass
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- The Effect of Combined Magnetic Geometries on Thermally Driven Winds II: Dipolar, Quadrupolar and Octupolar Topologies
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- Turbulent dynamo in a conducting fluid and partially ionized gas
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- Laminar and turbulent dynamos in chiral magnetohydrodynamics. II. Simulations
- Probability of CME Impact on Exoplanets Orbiting M Dwarfs and Solar-Like Stars
- XUV exposed, non-hydrostatic hydrogen-rich upper atmospheres of terrestrial planets II: Hydrogen coronae and ion escape
- Unsigned magnetic flux as a proxy for radial-velocity variations in Sun-like stars
- Physical constraints for the evolution of life on exoplanets
- Understanding solar cycle variability
- Solar cycle indices from the photosphere to the corona: measurements and underlying physics
- The Effect of Magnetic Variability on Stellar Angular Momentum Loss I: The Solar Wind Torque During Sunspot Cycles 23 & 24
- Observing the simulations: Applying ZDI to 3D non-potential magnetic field simulations
- A census of Coronal Mass Ejections on solar-like stars
- Magnetic Field of the Eclipsing M Dwarf Binary YY Gem
- On the timing properties of SAX J1808.4-3658 during its 2015 outburst
- The relative emission from chromospheres and coronae: dependence on spectral type and age
- The 0.8-4.5m broadband transmission spectra of TRAPPIST-1 planets
- Effective induction heating around strongly magnetized stars
- MOVES I. The evolving magnetic field of the planet-hosting star HD189733
- Activity Analyses for Solar-Type Stars Observed With Kepler. I. Proxies of Magnetic Activity
- Near-UV and optical observations of the transiting exoplanet TrES-3b
- Constraining atmospheric parameters and surface magnetic fields with : an application to SPIRou spectra
- Pressure Balance and Intrabinary Shock Stability in Rotation-Powered State Redback and Transitional Millisecond Pulsar Binary Systems
- 3D Radiative MHD simulations of starspots
- Radio pulse search and X-Ray monitoring of SAX J1808.4-3658: What Causes its Orbital Evolution?
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- TESS observations of flares and quasi-periodic pulsations from low mass stars and potential impact on exoplanets
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- Identifying solar-like magnetic cycles with Zeeman-Doppler-Imaging (ZDI)
- Can Sub-photospheric Magnetic Reconnection Change the Elemental Composition in the Solar Corona?
- A Comparison Between Physics-based and Polytropic MHD Models for Stellar Coronae and Stellar Winds of Solar Analogs
- Connecting the large- and the small-scale magnetic fields of solar-like stars
- Optical and near-infrared stellar activity characterization of the early M dwarf Gl~205 with SOPHIE and SPIRou
- Rotational modulation of spectroscopic Zeeman signatures in low-mass stars
- MHD study of extreme space weather conditions for exoplanets with Earth-like magnetospheres: On habitability conditions and radio-emission
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- Magnetogenesis at Cosmic Dawn: Tracing the Origins of Cosmic Magnetic Fields
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- First spectropolarimetric measurement of a brown dwarf magnetic field in molecular bands
- Equilibria, Dynamics and Current Sheets Formation in Magnetically Confined Coronae
- Application of a magnetic-field-induced transition in Fe X to solar and stellar coronal magnetic field measurements
- The large-scale magnetic field of the eccentric pre-main-sequence binary system V1878 Ori
- Recognition of M-type stars in the unclassified spectra of LAMOST DR5 using a hash learning method
- Unsigned magnetic flux proxy from solar optical intensity spectra
- Irradiance Variations of the Sun and Sun-Like Stars -- Overview of Topical Collection
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- New Suns in the Cosmos IV: the multifractal nature of stellar magnetic activity in \textit{Kepler} cool stars
- Dependence of magnetic cycle parameters on period of rotation in nonlinear solar-type dynamos
- Testing the solar activity paradigm in the context of exoplanet transits
- The multi-line slope method for the measure of the effective magnetic field of the cool stars: an application to the solar like cycle of ε Eri
- SpecpolFlow: a new software package for spectropolarimetry using Python
- Rotational threshold in global numerical dynamo simulations
- Measurements of the magnetic field strengths at the bases of stellar coronae using the magnetic-field-induced transition theory
- Zeeman Doppler Imaging of ksi Boo A and B
- Predictions of Astrometric Jitter for Sun-like Stars. III. Fast Rotators
- Far beyond the Sun: II. Probing the stellar magnetism of the young Sun ι Horologii from the photosphere to its corona
- Eclipsing Spotted Giant Star With K2 and Historical Photometry
- Superflares on solar-like stars: A new method for identifying the true flare sources in photometric surveys
- Reducing activity-induced variations in a radial-velocity time series of the Sun as a star
- A study of Pulsation & Rotation in a sample of A-K type stars in the Kepler field
- Observing Flare Stars Below 100 MHz with the LWA
- Interplay between tidal flows and magnetic fields in nonlinear simulations of stellar and planetary convective envelopes
- The impact of unresolved magnetic spots on high precision radial velocity measurements
- Subresolution Activity in Solar and Stellar Coronae from Magnetic Field Line Tangling
- Noise Sources in Photometry and Radial Velocities
- Forward Modeling of Magnetic-field Measurements at the Bases of Stellar Coronae through Extreme-Ultraviolet Spectroscopy
- Slow Magnetoacoustic Oscillations in Stellar Coronal Loops
- Magnetic field and radial velocities of the star Chi Draconis A
- Gl 725A b: a potential super-Earth detected with SOPHIE and SPIRou in an M dwarf binary system at 3.5 pc
- Measurement of stellar and substellar winds using white dwarf hosts
- Conversion and Damping of Nonaxisymmetric Internal Gravity Waves in Magnetized Stellar Cores
- Absolute dimensions of the F-type eclipsing binary V2154 Cygni
- X-ray and UV emission of the ultrashort-period, low-mass eclipsing binary system BX Tri
- The Effects of Sunspots on Spectral Line Shapes in the Visible
- Solar radius and luminosity variations induced by the internal dynamo magnetic fields
- Radio Emission from a Nearby M dwarf Binary
- Large-scale magnetic fields and anomalies of chemical composition of stellar coronae
- Gaia Calibrated UV Luminous Stars in LAMOST
- X-Ray and Ultraviolet Flares on AT Microscopii Observed by AstroSat
- The reason for the occurrence of W-type contact binaries
- Radiation Burst by Axion Star Collision with Star in the Andromeda Galaxy
- Coronal Mass Ejections and Exoplanets: A Numerical Perspective
- Uncovering the Dominant Spatial Scales of the Sun's Magnetic Field in Solar Cycle 24