limb darkening

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Related to limb darkening: limb brightening

limb darkening:

see sunsun,
intensely hot, self-luminous body of gases at the center of the solar system. Its gravitational attraction maintains the planets, comets, and other bodies of the solar system in their orbits.
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limb darkening

The decrease in intensity at visible wavelengths from the center to the limb of the Sun's disk. Light from the central portion of the disk is radiated radially toward us, whereas light from closer to the limb has to pass obliquely through a greater thickness of the solar atmosphere. For a given limit of penetration we can therefore see deeper into the photosphere at the center of the disk than at the limb, where our line of sight passes through cooler gases. The limb consequently appears less bright.

Limb darkening has been detected in other stars, principally by the use of three-color photometry of the light curves of eclipsing binaries (the effect being more pronounced in blue light than in red) and by speckle interferometry.

A similar effect is observed in planets with deep atmospheres, notably Jupiter and Saturn, and arises from the scattering of sunlight by atmospheric particles.

limb darkening

[′lim ‚där·kə·niŋ]
An observed darkening near the surface of the sun's limb as compared to its brighter center.
References in periodicals archive ?
In the end, the simplest explanation for limb darkening lies in the recognition that directional spectral emissivity occurs naturally within condensed matter [66, 71-73].
On Solar granulations, limb darkening, and sunspots: Brief insights in remembrance of Father Angelo Secchi.
Frank Very was the first to monitor the limb darkening of the Sun [12] as a function of frequency.
Thus, in the condensed matter scenario, limb darkening is an expression of angle of observation without having to make any arguments based on optical depth.