%0 Journal Article %1 BELL1991 %A BELL, J. F. %A MCCORD, T. B. %D 1991 %J PROCEEDINGS OF LUNAR AND PLANETARY Science %K DISK-INTEGRATED ICE; MIRANDA; PARAMETERS PHOTOMETRY; SATELLITES; SOLAR-SYSTEM; SPECTROPHOTOMETRY; SURFACE; UMBRIEL; URANUS VOYAGER-2; WATER %P 473--489 %T A SEARCH FOR SPECTRAL UNITS ON THE URANIAN SATELLITES USING COLOR RATIO IMAGES %V 21 %X We have analyzed 20 multispectral sets of calibrated, coregistered Voyager 2 images of the uranian satellites in an effort to identify spectrally (and thus possibly compositionally) distinct surface units and to associate these units with specific endogenic or exogenic surface processes. Morphologic unit mapping based on the initial work of Smith et al. (1986) has identified several regions on each satellite where significant spectral/compositional diversity could be expected. Color ratio images indicate that several of the satellites' surfaces exhibit significant color (as well as albedo) heterogeneity, and the majority of this heterogeneity is associated with impact craters. Oberon exhibits the highest degree of color variability, and we confirm the discovery by Helfenstein et al. (1990a) of a significant leading/trailing hemisphere color asymmetry. Titania and Ariel also show measurable impact-associated color variability, and we report on the possible existence of a hemispherical color asymmetry similar to Oberon's for Titania. Miranda (surprisingly) and Umbriel are very spectrally homogeneous. Several mechanisms for the origin of the color variability are discussed, including the possibility of an outer solar system analog to lunar vitrification darkening/reddening.

@article{BELL1991, abstract = {We have analyzed 20 multispectral sets of calibrated, coregistered Voyager 2 images of the uranian satellites in an effort to identify spectrally (and thus possibly compositionally) distinct surface units and to associate these units with specific endogenic or exogenic surface processes. Morphologic unit mapping based on the initial work of Smith et al. (1986) has identified several regions on each satellite where significant spectral/compositional diversity could be expected. Color ratio images indicate that several of the satellites' surfaces exhibit significant color (as well as albedo) heterogeneity, and the majority of this heterogeneity is associated with impact craters. Oberon exhibits the highest degree of color variability, and we confirm the discovery by Helfenstein et al. (1990a) of a significant leading/trailing hemisphere color asymmetry. Titania and Ariel also show measurable impact-associated color variability, and we report on the possible existence of a hemispherical color asymmetry similar to Oberon's for Titania. Miranda (surprisingly) and Umbriel are very spectrally homogeneous. Several mechanisms for the origin of the color variability are discussed, including the possibility of an outer solar system analog to lunar vitrification darkening/reddening.}, added-at = {2009-11-03T20:21:25.000+0100}, author = {BELL, J. F. and MCCORD, T. B.}, biburl = {https://www.bibsonomy.org/bibtex/2bb431684c226b530ee15312713ca5e09/svance}, citedreferences = {ADAMS JB, 1971, Science, V171, P567 ; BELL JF, 1979, B AM ASTRON SOC, V11, P570 ; BELL JF, 1990, LUNAR PLANET SCI, V21, P58 ; BROWN RH, 1983, Icarus, V56, P414 ; BROWN RH, 1984, Icarus, V58, P288 ; BURATTI B, 1990, Icarus, V84, P203 ; BURNS RG, 1970, MINERALOGICAL APPLIC ; CALCAGNO L, 1985, Icarus, V63, P31 ; CLARK RN, 1984, J GEOPHYS RES, V89, P6329 ; CROFT SK, 1987, LUNAR PLANET SCI, V18, P207 ; CROFT SK, 1990, IN PRESS URANUS ; CRUIKSHANK DP, 1980, Icarus, V41, P246 ; CRUIKSHANK DP, 1981, Icarus, V45, P607 ; CRUIKSHANK DP, 1983, Icarus, V53, P90 ; DANIELSON GE, 1981, J GEOPHYS RES, V86, P8583 ; DAVIES ME, 1987, Icarus, V71, P137 ; HARRIS DL, 1961, PLANETS SATELLITES, P272 ; HELFENSTEIN P, 1988, Icarus, V74, P231 ; HELFENSTEIN P, 1989, LUNAR PLANET SCI, V20, P402 ; HELFENSTEIN P, 1989, Nature, V338, P324 ; HELFENSTEIN P, 1990, IN PRESS Icarus ; HELFENSTEIN P, 1990, LUNAR PLANET SCI, V21, P489 ; HILLIER J, 1989, Icarus, V82, P314 ; JANES DM, 1988, J GEOPHYS RES, V93, P3127 ; JANKOWSKI DG, 1988, Science, V241, P1322 ; JOHNSON PE, 1978, Icarus, V36, P75 ; JOHNSON TV, 1987, J GEOPHYS RES, V92, P14884 ; MATSON DL, 1977, 8TH P LUN SCI C, P1001 ; MCCORD TB, 1972, J GEOPHYS RES, V77, P1349 ; PLESCIA JB, 1987, J GEOPHYS RES-SPACE, V92, P14918 ; REITSEMA HJ, 1978, B AM ASTRON SOC, V10, P585 ; SHOEMAKER EM, 1982, SATELLITES JUPITER, P277 ; SINTON WM, 1977, Science, V198, P503 ; SMITH BA, 1982, Science, V215, P504 ; SMITH BA, 1986, Science, V233, P43 ; SODERBLOM LA, 1970, J GEOPHYS RES, V75, P2655 ; SOIFER BT, 1981, Icarus, V45, P612 ; STRAZZULLA G, 1983, MON NOT R ASTRON SOC, V204, P59 ; STROM RG, 1987, Icarus, V70, P517 ; THOMAS PC, 1987, J GEOPHYS RES-SPACE, V92, P14911 ; THOMPSON WR, 1987, J GEOPHYS RES-SPACE, V92, P14933 ; THOMSEN B, 1978, B AM ASTRON SOC, V10, P581 ; VEVERKA J, 1987, J GEOPHYS RES-SPACE, V92, P14895 ; VEVERKA J, 1989, Icarus, V78, P14 ; WENDLANDT WW, 1966, REFLECTANCE SPECTROS}, interhash = {a04187977832f428bccf01ae1218a879}, intrahash = {bb431684c226b530ee15312713ca5e09}, journal = {PROCEEDINGS OF LUNAR AND PLANETARY Science}, keywords = {DISK-INTEGRATED ICE; MIRANDA; PARAMETERS PHOTOMETRY; SATELLITES; SOLAR-SYSTEM; SPECTROPHOTOMETRY; SURFACE; UMBRIEL; URANUS VOYAGER-2; WATER}, owner = {svance}, pages = {473--489}, timestamp = {2009-11-03T20:21:39.000+0100}, title = {A SEARCH FOR SPECTRAL UNITS ON THE URANIAN SATELLITES USING COLOR RATIO IMAGES}, volume = 21, year = 1991 }