1999MNRAS.310..784F -
Mon. Not. R. Astron. Soc., 310, 784-788 (1999/December-2)
The nanoflare model and stellar quiescent radio emission.
FALLA D.F. and POTTER A.G.
Abstract (from CDS):
The concept of the nanoflare, used in interpreting the solar X-ray corona, is extended to RS CVn stars which, unlike the Sun, exhibit non-thermal quiescent radio spectra. The theoretical synchrotron-radiation radio spectrum emitted by a regular series of nanoflare-electron pulses, injected into the coronal magnetic field, is derived: for an electron energy spectrum N(γ)∝γ–s, the spectral power density is given by P(ν)∝ν–s/2. This result is valid for the observation of a series of nanoflares with total time duration ≳ the characteristic electron radiation lifetime, which is the case for electrons trapped in extensive coronal regions such as exist in RS CVn stars on the magnetic-dipole magnetospheric model. The tenuous coronal plasma allows the electrons to give a radio spectrum unaffected at high frequencies (≳5GHz) by electron collision loss, while the emission of bremsstrahlung X-rays by the electrons also occurs with a spectrum that is related to their radio emission. The observation of individual X-ray bursts, which would provide direct evidence for microflares, is not, however, attainable with current instrumentation.
Abstract Copyright:
1999, Royal Astronomical Society
Journal keyword(s):
radiation mechanisms: non-thermal - stars: coronae - stars: individual: UX Arietis - stars: magnetic fields - radio continuum: stars - X-rays: stars
Simbad objects:
2
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