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The surface brightness in magnitude units is related to the surface brightness in physical units of solar luminosity per square parsec by [citation needed] (/) = + (/), where and are the absolute magnitude and the luminosity of the Sun in chosen color-band [8] respectively.
As the radius increases, the surface area will also increase, and the constant luminosity has more surface area to illuminate, leading to a decrease in observed brightness. =, where is the area of the illuminated surface. is the flux density of the illuminated surface.
Surface brightness fluctuation (SBF) is a secondary distance indicator used to estimate distances to galaxies. It is useful to 100 Mpc ( parsec ). The method measures the variance in a galaxy's light distribution arising from fluctuations in the numbers of and luminosities of individual stars per resolution element.
Hertzsprung–Russell diagram – relates absolute magnitude or luminosity versus spectral color or surface temperature. Jansky radio astronomer's preferred unit – linear in power/unit area; List of most luminous stars; Photographic magnitude; Surface brightness – the magnitude for extended objects
Apparent magnitude, the brightness of an object as it appears in the night sky. Absolute magnitude, which measures the luminosity of an object (or reflected light for non-luminous objects like asteroids ); it is the object's apparent magnitude as seen from a specific distance, conventionally 10 parsecs (32.6 light years ).
(The S 10 unit is defined as the surface brightness of a star whose V-magnitude is 10 and whose light is smeared over one square degree, or 27.78 mag arcsec −2.) The total sky brightness in zenith is therefore ~220 S 10 or 21.9 mag/arcsec² in the V-band. Note that the contributions from Airglow and Zodiacal light vary with the time of year ...
Illuminance diagram with units and terminology. In photometry, illuminance is the total luminous flux incident on a surface, per unit area. [1] It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate with human brightness perception. [2]
Globular cluster luminosity function (GCLF) Surface brightness fluctuation (SBF) In galactic astronomy, X-ray bursts (thermonuclear flashes on the surface of a neutron star) are used as standard candles. Observations of X-ray burst sometimes show X-ray spectra indicating radius expansion.