Albedo geometric

Figure 1 Spectral geometric albedo (1.0 = white disk of same radius) of the Galilean satellites. Hemispheric average values from telescopic observations (after Clark and McCord, 1980a).

Nelson R. M., Lane A. L., Matson D. L., Veeder G. J., Buratti B. J., and Tedesco E. F. (1987) Spectral geometric Albedos of the Galilean satellites from 0.24 to 0.34 micrometers— observations with the international ultraviolet explorer. Icarus 72, 358-380. 

Geometric albedo, which is a measure of the fraction of incident sunlight reflected by the satellite. 

The geometric albedo A of a particle is defined as the ratio of the energy scattered at a = 0 to that scattered by a white Lambert disk of the same... 

Figure 5. The geometric albedo Ap and polarization P for randomly oriented BCCA (shown by lines) and BPCA (shown by symbols) aggregates consisting of optically dark submicron grains. Solid lines and crosses are the numerical results for /l=0.45 pm and dotted curves and circles are for 1=0.60 pm. Dashed horizontal straight lines in the upper left comer of each lower panel illustrate P=0. The number of constituent particles in the aggregate is N=64 (left panel), 128 (middle panel), or 256 (right panel).

Fig. 8.5.2 Variation of flux and linear polarization with orbital longitude due to a single standard hot spot of area 2000 km (T = 450 K) located at 180° W, 15°N on a model planet with n = 1.5 and a true geometric albedo of 0.8. In each frame of the figure, the solid line is the signature of this standard spot and the broken lines show the changes in this signature if one of the parameters is varied from the standard configuration, (a) The quasi-geometric albedo p (b) the degree of linear polarization V (dotted line, n = 1.8) (c) azimuth of linear polarization f (dashed line, latitude 45°N dotted line, latitude 15°S) (Goguen Sinton, 1985).

Recent determinations of the geometric albedos, the phase integrals, and the Bond albedos for the outer planets are summarized in Table 8.6.1. References indicating the sources of the quoted values are also shown. The measurement of the Saturn albedo is complicated by the existence of the ring system, which not only casts a shadow on Saturn but also scatters additional sunlight towards that planet. Both effects vary over the Saturnian year due to the relatively large inclination of the equator towards the orbital plane ( 27°). 

Using the same on-board calibration with the diffuse reflecting plate, a geometric albedo of 0.242 0.012 was derived. Again combining this with a Pioneer-derived phase integral led to a Bond albedo of 0.342 0.030. Because of the uncertainty of the radiometer calibration this number must be taken with the same reservations as the corresponding number for Jupiter. 

Near-infrared spectral geometric albedos of Charon and Pluto Constraints on Charon s surface composition. Icarus, 119, 214-18. 

Yang and Jewitt, 2007 [368] searched for spectral signatures of water ice on Trojan asteroids.Trojans (911) Agamemnon, (617) Patroclus, (1143) Odysseus, and (2797) Teucer were observed. These objects have been independently reported to show possible weak absorptions at 1.7 and 2.3 pm, respectively. If real, the latter features may be due to organic materials present on the surfaces. Trojan (4709) En-nomos has a geometric albedo significantly above the mean Trojan albedo, perhaps because a recent impact has coated part of the surface with freshly excavated ice. 

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