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Moscow, IKI, October 10-14, 2011 PHOTOMETRIC AND RADIOMETRIC PROPERTIES OF PHOBOS REGOLITH FROM DATA GATHERED BY THE PHOBOS MISSION L.V. Ksanfomality, Space research institute of the RAS Space research institute of the RAS Moscow Moscow The second Moscow Solar system symposium Slide 2 KRFM PHOBOS-2 KRFM PHOBOS-2 1989 1989 Slide 3 Slide 4 March 25, 1989 Slide 5 Slide 6 The KRFM instrument operated in 9 photometric channels (325, 328, 346, 363, 410, 445, 488, 550 and 600 nm) and 6 radiometric channels (4.8-6.4, 6.1-7.8, 7.2-9.3, 9.2-13.6, 14.3-15.9, and 16.5- 49 mcm) Slide 7 Slide 8 Slide 9 Slide 10 The geometric albedo ( n ) = N tm F / , where is photometric function including two quantities, phase function () and function f of zenith distances of the Sun z s and of the spacecraft z a : (, z s, z a ) = f (z s, z a ). The approach of Lumme for large particles (2 r/ >>1) was used: () = (1 ) 1 () + (), With 1 () for single and () for multiple scattering. Slide 11 Slide 12 Slide 13 Slide 14 Slide 15 Slide 16 All the highly degraded craters along track 1 possess albedo from 4.8 to 6.8%, at wavelengths in the range 490-600 nm and from 3.1 to 4.0% at wavelengths in the range 330-410 nm. Conversely, the comparatively young craters have reduced albedo, for example, both the crater at 187W and the neighboring crater at 197W. Their albedo is lower, from 2.8 to 3.2% in the short-wave channel, and from 4.1 to 5.2% in the long- wave channel. In darker region along track 2, the albedo in the range 550-600 nm rapidly falls from 5.4 to 4.1%. In the short- waves (330-410 nm), the drop in albedo is less noticeable, from 3.2-3.5 to 2.9-3.0%. The minimum near 232 W represents a large, well-preserved crater with center at 25 N, 245 W. The albedo drops in the range 410-600 nm as approaching this crater, which is reasonable to associate with ejecta from the crater. Slide 17 Slide 18 Some publications of 1989 1997 Ksanfomality L.V., Moroz V.I. Spectral reflectivity of the Phobos regolith. // Icarus, 1995, v.117, pp.383-401. Moroz V.I., E.V.Petrova, L.V.Ksanfomality. Spectrophotometry of Mars in the KRFM experiment of the PHOBOS mission: some properties of the particles of atmospheric aerosols and the surface // Planet. Space Sci., 1993, v.41, N8, pp.569-585. Kuhrt E., B.Giese, H.U.Keller, L.V.Ksanfomality. Interpretation of the KRFM- Infrared measurements of Phobos. // Icarus, 1992, v. 96, pp.213-218. Ksanfomality L.V., S.Murchie., D.Britt, T.Duxbury, P.Fisher, N.Goroshkova, J.Head, E.Kuhrt, V.Moroz, B.Murray, G.Nikitin, E.Petrova, C.Pieters, A.Soufflot, A.Zharkov, B.Zhukov. // Phobos: spectrophotometry between 0.3 and 0.6 mcm and IR-radiometry // Planet. Space Sci., 1991, v.39, N1/2, pp.311-326. .. // . ., 1991, .25, N6, .650-676. Kuhrt E., B.Giese. A thermal model of the Martian satellites. // Icarus, 1989, v. 81, pp. 102-112. .., .., .. // , 1997. .31, 5, . 422-426. Slide 19 THE END