Solar Radio Astronomy

The influence of stellar wind conditions on the detectability of planetary radio emissions

“…The components differ in intensity and rate of occurrence and are caused by different emission Boischot & Denisse (1964) (dotted line) and Nelson et al (1985) (solid lines). The quiescent stellar emission of the dG0e star HD 129333 (=EK Dra) measured at 8.4 GHz (Güdel et al 1995) as well as that of the dM5.5e star UV Cet (short dashed line, from Güdel & Benz 1996) are normalized to a distance of 1 AU for comparison (see Sect.…”

“…This leads to a flux density variation by a factor of ∼2 at centimetre and decimetre wavelengths (Sheridan & McLean 1985). It has a periodicity of 27 days due to solar rotation (Boischot & Denisse 1964) and varies over the sunspot cycle. While the quiet sun emission is randomly polarized (Sheridan & McLean 1985), the emission in the centimetric range is often circularly polarized, which can only be explained by the strong magnetic fields of the sunspots (Boischot & Denisse 1964).…”

“…Due to their occurrence rate and their duration, noise storms significantly contribute to the signal detected: near solar maximum, noise storms occur about 10% of the time (Hjellming 1988). The typical duration of a noise storm is between a few hours and several days (Boischot & Denisse 1964;Warmuth & Mann 2005). Type I noise storms consist of a slowly varying broadband continuum plus shortlived bursts.…”

“…Type I noise storms consist of a slowly varying broadband continuum plus shortlived bursts. The emission of type I storms is highly circularly polarized (Boischot & Denisse 1964;Kai et al 1985). Type III storms are not associated with flares; they are connected to type III bursts (see above).…”

Low-Frequency Observations of Drifting, Non-Thermal Continuum Radio Emission Associated With the Solar Coronal Mass Ejections

“…The reader is referred to the review by Stewart (1985) for details. It is more than half a century since the discovery of the moving type IV bursts (Boischot & Denisse 1957), but simultaneous white-light, radioheliograph and radio spectrograph observations (the latter particularly almost until the low-frequency cut-off for ground-based radio observations) of the bursts have rarely been reported. While the heliograph and white-light coronagraph observations help to establish the spatial correspondence between the location of the radio burst and the CME, the spectrograph observations are required to identify the spectral nature of the observed emission from the presence/absence of drift in the emission frequency of the bursts as a function of time and also constrain the electron density.…”