No abstract available

[en] We present an analysis of facular/network and sunspot areas (and their ratio) covering most of cycle 22 and all of cycle 23. The data are corrected areas (in microhemispheres) from full-disk solar images using two photometric telescopes at the San Fernando Observatory, CFDT1 and CFDT2. Images from CFDT2 have approximately twice the spatial resolution of CFDT1. Sunspot areas are obtained from red images where spots are determined as those pixels darker than -8.5%. Facular/network areas are from Ca II K-line images where facular/network pixels are brighter than 4.8%. Regressions of facular area versus spot area for CFDT1 give a slope term of 25. For CFDT2, the slope term is 33. The average ratio of facular to spot area for cycle 22 is 45 and for cycle 23 the ratio is 42. These values are substantially higher than those from earlier studies. The increase is due to a combination of higher spatial resolution and the removal of a correction factor in μ. For the 0.3 nm K-line images, the spot to facular/network ratio is 138 for six years of cycle 23. A relation is given for the dependence of facular/network area on contrast. The relationship of facular/network area to sunspot area is linear for data from both telescopes.

[en] We present monochromatic observations, obtained with a 512 element diode array, of the irradiance fluctuations of the sunspots and faculae of an active region during its disk transit in 1982 August. Bolometric and stray light corrections are approximately equal in magnitude but opposite in sign, so they have not been applied. The maximum sunspot fluctuation, as a fraction of the quiet-Sun irradiance, is -800 parts per million (ppm). Faculae have a maximum irradiance fluctuation of about +200 ppm near the limbs. We find that the facular energy excess is more than 50% of the sunspot energy deficit, which is -5.8 x 10³⁵ ergs. These observations show that faculae are an important element in active region energy balance

[en] A new semiempirical model of photospheric faculae is presented in tabular form. In an earlier paper (Chapman) a preliminary version of this model was used to construct line profiles that were compared with observations. The magnetic field is estimated from horizontal pressure equilibrium without tension forces. The geometry of the flux tube is determined from this estimated magnetic field and an assumed flux of 4.4 x 10¹⁷ gauss cm². The model is discussed in relation to recent observations

[en] An improved semi-empirical model of photospheric faculae is presented in tabular form. The limitations of the model as well as other possible improvements are discussed

[en] Measurements of the contrast at 525 nm of solar faculae are presented. These measurements were obtained with an extreme limb photometer (ELP) in 19775 and 1979 at the San Fernando Observatory. The mean contrast of active regions was determined from the limb inward to 54'', averaged over an annulus determined by the slits of the ELP. We find that the contrast of faculae increases with heliocentric angle theta, from μroughly-equal0.25 to μroughly-equal0.065, where μ = cos theta. The average value of the mean contrast of facular regions is 2.1% with a possible upper limit of about 5% at μroughly-equal0.1, determined from regions with the greatest filling factor. This mean contrast, when corrected for a filling factor of 10-15% implies a contrast for individual faculae of 30-50%. The results from the two observing seasons, when combined, are not inconsistent with the μ-dependence of the excess solar oblateness signal measured at Princeton in 1966. The 1979 facular data would have produced an apparent excess oblateness of 66% of the Dicke and Goldenberg value. Because the contrast of faculae appears to increase to within a few arcsec of the limb, the excess facular intensity is probably due not only to ''hot wall'' effects but also to local heating in the upper levels of facular flux tubes

[en] The Glossary is designed to be a technical dictionary that will provide solar workers of various specialities, students, other astronomers and theoreticians with concise information on the nature and properties of phenomena of solar and solar-terrestrial physics. Each term or group of related terms, is given a concise phenomenological and quantitative description, including the relationship to other phenomena and an interpretation in terms of physical processes. The references are intended to lead the non-specialist reader into the literature. This section deals with: photospheric faculae; facular point; polar faculae; magnetic knots; moving magnetic features; pore; sunspot; umbra; umbral dots; flashes and oscillations; light bridges; penumbra; penumbral waves; Evershed effect; and Wilson effect. (B.R.H.)

No abstract available

[en] Detailed studies of the development of photospheric activity centres for two solar cycles show that Spoerer's Law holds in a very similar form to that applying to sunspots for the faculae which inhabit the sunspot zones. Similar differences between the two solar hemispheres can arise, and it seems to be confirmed that the average latitude of faculae tends to be a few degrees poleward of that of sunspots throughout a given cycle. It is shown that the normal averaging process involved in deriving Spoerer's Law obscures a detail which is revealed in a breakdown into the variations within successive narrow latitude strips. These show the existence within a cycle of three separate maxima of activity occurring at different epochs and with different preferred latitudes. The main properties of these maxima are discussed. (orig.)

No abstract available