Quiescent Non-thermal Radio Emission from Stellar Systems

Storey, Michelle C.; Hewitt, R.G.L.

doi:10.1017/s1323358000020233

Cited by 5 publications

(3 citation statements)

References 17 publications

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“…Particles accelerated in that region travel back and are trapped in the dipolar-like, equatorial magnetospheric cavity. Variants of this radiation belt model, partly based on theoretical work of Havnes & Goertz (1984), have been applied to RS CVn binaries (Slee et al 1987b, Morris et al 1990, Jones et al 1994, Storey & Hewitt 1996, in an optically thick version to Bp/Ap stars (Drake et al 1987b and in an optically thin version to a young B star (André et al 1988).…”

Section: Magnetospheric Modelsmentioning

confidence: 99%

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Stellar Radio Astronomy: Probing Stellar Atmospheres from Protostars to Giants

Guêdel

2002

Annu. Rev. Astron. Astrophys.

331

350

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▪ Abstract Radio astronomy has provided evidence for the presence of ionized atmospheres around almost all classes of nondegenerate stars. Magnetically confined coronae dominate in the cool half of the Hertzsprung-Russell diagram. Their radio emission is predominantly of nonthermal origin and has been identified as gyrosynchrotron radiation from mildly relativistic electrons, apart from some coherent emission mechanisms. Ionized winds are found in hot stars and in red giants. They are detected through their thermal, optically thick radiation, but synchrotron emission has been found in many systems as well. The latter is emitted presumably by shock-accelerated electrons in weak magnetic fields in the outer wind regions. Radio emission is also frequently detected in pre–main sequence stars and protostars and has recently been discovered in brown dwarfs. This review summarizes the radio view of the atmospheres of nondegenerate stars, focusing on energy release physics in cool coronal stars, wind phenomenology in hot stars and cool giants, and emission observed from young and forming stars. Eines habe ich in einem langen Leben gelernt, nämlich, dass unsere ganze Wissenschaft, an den Dingen gemessen, von kindlicher Primitivität ist—und doch ist es das Köstlichste, was wir haben. One thing I have learned in a long life: that all our science, measured against reality, is primitive and childlike—and yet it is the most precious thing we have. A. Einstein 1951, in a letter to H. Mühsam, Einstein Archive 36-610

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Section: Magnetospheric Modelsmentioning

confidence: 99%

“…This issue is unresolved. Arguments for small-scale coronal active regions as well as for star-sized global magnetospheres have been put forward (see discussions in White et al 1989b, Morris et al 1990, and Storey & Hewitt 1996.…”

Section: Introductionmentioning

confidence: 99%

Stellar Radio Astronomy: Probing Stellar Atmospheres from Protostars to Giants

Guêdel

2002

Annu. Rev. Astron. Astrophys.

331

350

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“…The magnetic dipole axis is assumed to be parallel to the rotation axis of the system. Such axisymmetry is implied by observations of quiescent emission from RS CVn binary systems (Morris, Mutel, & Su 1990 ;Storey & Hewitt 1995). A dipole-shaped magnetic Ðeld is chosen, while keeping in mind that it is an approximation to what is probably a complex magnetic conÐguration.…”

Section: Modelmentioning

confidence: 99%

Nonthermal Radio Emission from the Precataclysmic Binary System V471 Tauri

Nicholls

Storey

1999

ApJ

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Recent observations have presented strong evidence for the existence of eclipses in the nonthermal radio emission from the precataclysmic binary system V471 Tau. In this paper we calculate the gyrosynchrotron emission from models assuming a dipole-shaped magnetosphere and a magnetized wind around the K dwarf. The model assumes that electrons are accelerated to mildly relativistic energies in the region where the magnetic Ðelds of the two stars interact and become trapped in the K dwarfÏs magnetosphere. Comparison with the data indicates that azimuthal drift and energy loss lead to a region of enhanced density of mildly relativistic electrons, extending for over 100¡ in azimuth and preceding the white dwarf in phase. The data is best Ðtted by models assuming a power-law drop with azimuthal angle of this enhancement in mildly relativistic electron density.

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Radiation transfer of gyrosynchrotron emission in stellar environments

Storey

1996

Sol Phys

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Non-thermal radio emission has been detected from several kinds of active stars. Polarization and intensity measurements of the quiescent (i.e. non-flaring) emission indicate gyrosynchmtron crnission. A three-dimensional magnetic lield model for the stellar field is presented anti the gyrosynchrolron intensity and polarization emerging from such a model is calculalcd and compared with obserwations. Model spectra agree well with observations. Model polarization restdts indicate that the emission region is morc complex than the simple model and may indicate the prcscncc ~yf multipolc components in the field, small loops of llux near the stellar surface and significanl energy loss in the radiating electron distribution over time.

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Quiescent Non-thermal Radio Emission from Stellar Systems

Cited by 5 publications

References 17 publications

Stellar Radio Astronomy: Probing Stellar Atmospheres from Protostars to Giants

Stellar Radio Astronomy: Probing Stellar Atmospheres from Protostars to Giants

Nonthermal Radio Emission from the Precataclysmic Binary System V471 Tauri

Radiation transfer of gyrosynchrotron emission in stellar environments

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