EPSC Abstracts, Vol. 4, EPSC2009-314, 2009 European Planetary Science Congress, © Author(s) 2009
The Illumination Conditions of the South Pole Region Of The Moon
E.A.Kozlova. (1) Sternberg State Astronomical Institute, Moscow State University. [email protected]
The “Lunar Prospector” spacecraft, horizon during only 24% time of diurnal period for launched by NASA toward the Moon in 1998, this point. revealed the areas of high hydrogen content near Fig.2. shows the topographic profile of the both poles of the Moon. The South Pole of the crater Shoemaker (88º S, 38º E, D = 51 km) Moon is located in the southern part of the giant accordingly to date from KAGUYA (SELENE). topographic depression – the South Pole - Aitken The average depth of a crater has made 3,1 kms, basin. This region is heavily cratered and some an inclination of walls - 13º. The small crater is in craters at the poles are never exposed to direct the central part of the flat floor of Shoemaker. sunlight. High hydrogen content was found in the Earlier, we computed the permanently areas coinciding with such craters as Shoemaker shadowed area in the polar regions of the Moon (88º S, 38º E) and Faustini (87,2º S, 75,8º E) and for the real distribution of craters taking into other craters [1]. These craters can presumably be account the variations of the elevation of the Sun considered as "cold traps" in the South Polar during the 230 solar days that make up the period region of the Moon. of regression of the nodes of the lunar orbit [3]. In this work we used the laser altimeter data onboard the Japanese lunar orbiter KAGUYA (SELENE) [2] to obtain the illumination condition Distance (km) 0 near South Pole of the Moon for the diurnal 1 6 11 16 21 26 31 36 41 46 51 56 61 66 -500 variation in the altitude of the sun above the -1000 horizon (Fig.1). -1500
-2000 Degrees -2500
8 (m) Topography -3000
7 -3500 Horizon -4000 6 -4500 5 Sun Figure 2: Topographic profiles of crater 4 Shoemaker (88º S, 38º E, D = 51 km) at 88º S. 3 According to these results the permanently 2 shaded area is occur 59% of inner part of crater 1 Shoemaker, and 50 % of inner part of craters 0 Faustini. The altimetry date from KAGUYA 1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 (SELENE) [2] was used to calculate the permanently shaded area in these craters. Azimuth of the sun interval According to our results the crater Shoemaker is
one of the most shadowed among large craters: it Figure 1: Diurnal variation in the altitude of the has 65% of its area permanently shadowed. The 59 sun and the high of horizon for the point in the % of inner part of crater Faustini remained in central part of crater Shoemaker. The x-axis is the shadow during a lunar day. number of the sun azimuth interval, each separated The lighting conditions were mapped over a by 2,5º. The altitude of the sun exceeds the region of the crater Shoemaker and Faustini (Fig.3).
EPSC Abstracts, Vol. 4, EPSC2009-314, 2009 European Planetary Science Congress, © Author(s) 2009
Figure 3: Illumination map of the craters Shoemaker and Faustini region. S – crater Shoemaker, F – crater Faustini.
References: [1] Feldman W.C. et al. (2001) J. Geophys. Res., V. 106, p. 23231-23252. [2] http: wms.selena. jaxa. jp [3] Kozlova E.A. et al. (2001) 34-th Int. Microsymp. on Planetology. Abstr. #MS065.
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