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

KRFM PHOBOS-2 KRFM PHOBOS

March 25, 1989

The KRFM instrument operated in 9 photometric channels (325, 328, 346, 363, 410, 445, 488, 550 and 600 nm) and 6 radiometric channels ( , , , , , and mcm)

The geometric albedo ρ (λ n ) = N tm β F / Φ, where Φ is photometric function including two quantities, phase function θ(α) and function f of zenith distances of the Sun z s and of the spacecraft z a : Φ (α, z s, z a ) = f (z s, z a ). The approach of Lumme for large particles (2 πr/ λ >>1) was used: θ(α) = (1 – Г) θ 1 (α) + Г θ м (α), With θ 1 (α) – for single and θ м (α) for multiple scattering.

All the highly degraded craters along track 1 possess albedo from 4.8 to 6.8%, at wavelengths in the range nm and from 3.1 to 4.0% at wavelengths in the range nm. Conversely, the comparatively young craters have reduced albedo, for example, both the crater at 187°W and the neighboring crater at 197°W. 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 nm rapidly falls from 5.4 to 4.1%. In the short- waves ( nm), the drop in albedo is less noticeable, from to %. The minimum near 232° W represents a large, well-preserved crater with center at 25° N, 245° W. The albedo drops in the range nm as approaching this crater, which is reasonable to associate with ejecta from the crater.

Some publications of 1989 – 1997 Ksanfomality L.V., Moroz V.I. Spectral reflectivity of the Phobos regolith. // Icarus, 1995, v.117, pp 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 Kuhrt E., B.Giese, H.U.Keller, L.V.Ksanfomality. Interpretation of the KRFM- Infrared measurements of Phobos. // Icarus, 1992, v. 96, pp 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 Ксанфомалити Л.В. Фотометрические свойства реголита Фобоса по данным миссии ФОБОС // Астрономич. Вестн., 1991, т.25, N6, с Kuhrt E., B.Giese. A thermal model of the Martian satellites. // Icarus, 1989, v. 81, pp Ксанфомалити Л.В., Петрова Е.В., Хартманн У.К. Неоднородность реголита Фобоса по степени зрелости // Астрономический вестник, Т.31, 5, с

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