albedo is the term for the percentage of light reflected by something.
albedo is the term for the percentage of light reflected by something.
what is the term for the percentage of light reflected by something?
albedo
stars shine intrinsically, but they can also reflect light. in a close binary star system polarimetry can be used to measure the light reflected from one star off another (and vice versa) and therefore also the geometric albedos of the two stars. this task has been accomplished for the two components of the spica system, with the geometric albedo of spica a and b being measured as 0.0361 and 0.0136 respectively. the geometric albedos of stars are in general small, for the sun a value of 0.001 is expected, but for hotter of lower gravity (i.e. giant) stars the amount of reflected light is expected to be several times that of the stars in the spica system.
geometric albedo
note that this principle only holds strictly for light reflected at normal incidence. for instance, right circularly polarized light reflected from a dielectric surface at grazing incidence (an angle beyond the brewster angle) will still emerge as right handed, but elliptically, polarized. light reflected by a metal at non-normal incidence will generally have its ellipticity changed as well. such situations may be solved by decomposing the incident circular (or other) polarization into components of linear polarization parallel and perpendicular to the plane of incidence, commonly denoted "p" and "s" respectively. the reflected components in the "p" and "s" linear polarizations are found by applying the fresnel coefficients of reflection, which are generally different for those two linear polarizations. only in the special case of normal incidence, where there is no distinction between "p" and "s", are the fresnel coefficients for the two components identical, leading to the above property.
circular polarization