Map of Moon and Mercury roughness
ISBN 978-85-88783-11-9
Authors
1Kokhanov, A.; 2Karachevtseva, I.; 3Kreslavsky, M.
1MOSCOW STATE UNIVERSITY OF GEODESY AND CARTOGRAPHY Email: s_kokhanov@mexlab.ru
2MOSCOW STATE UNIVERSITY OF GEODESY AND CARTOGRAPHY Email: i_karachevtseva@miigaik.ru
3MOSCOW STATE UNIVERSITY OF GEODESY AND CARTOGRAPHY Email: mkreslav@ucsc.edu
Abstract
Topographic roughness maps of Mercury at different baselines were created with the latest data acquired by Mercury Laser Altimeter (MLA) onboard MESSENGER mission. Although the altimeter data are available for the northern polar regions of the planet only, they provide a new look at the features of topography of Mercury. The obtained preliminary results indicate a clear distinction between relatively smooth plains and rough areas of the northern hemisphere of Mercury; they also enable a comparison with statistical characteristics of topography of the Moon. Roughness maps in some sense can carry more information, than topographic maps or images of surface. Usually the planar distance between orbital laser altimeter measurements is less than a typical distance between orbits. As a result, the spatial resolution of topographic data is much better, than spatial resolution of derived topographic maps. Mapping of roughness. In this research we calculate roughness on the base of MLA (Cavanaugh et al., 2007) data. Due to amount of laser altimeter measurements and eccentricity of the spacecraft orbit by this time we able to crate map only for the northern subpolar area of Mercury between 65° and 84°N. For the Moon, we used LOLA-derived lunar roughness map (Kreslavsky et al., 2013) The topographic roughness was calculated as the interquartile range of along-profile curvature at three baselines: 0.7, 2.8 and 11.2 km. The most obvious feature on these color maps is the dichotomy between smooth plains and rough cratered regions, which is similar to the lunar dichotomy between mare and highland areas. However, roughness of cratered areas on Mercury is lower than that of lunar highlands calculated the same way. The layout contains: map of the lunar roughness on base 0.48 km (1:7 000 000) and map of the Mercury roughness on base 0.7 km (1:10 000 000). Both of maps are projected in oblique orthographic projection for the best representation of the northern sub-polar areas. While the whole Moon surface is covered by the roughness data combined with hill-shade, on Mercury only the northern sub-polar area has roughness data, and MDIS mosaic (http://www.messenger-education.org) is used on the other areas. According to the IAU recommendations (Archinal et al., 2011) the longitude on the Moon is defined from 0° to 360° with east-positive direction, while on Mercury, from 0° to 360° with west-positive direction. Created maps can be used for comparative analysis of the differences surface of celestial bodies, which is an important aspect of the appli-cation of cartographic methods in planetary research. For example, roughness of cratered terrains in the mapped area of Mercury is lower than that of lunar highlands. Detail analysis of this difference is an interesting study that can be done with the map. Acknowledgments: This work was carried out in MIIGAiK and supported by Russian Science Foundation, project #14-22-00197 References: Archinal, B. A., A′Hearn, M. F., Bowell, E., Conrad, A., Consolmagno, G. J., Courtin, R., Fukushima, T., Hestroffer, D., Hilton, J. L., Krasinsky, G. A., Neu-mann, G., Oberst, J., Seidelmann, P. K., Stooke, P., Tholen, D. J., Thomas, P. C., Williams, I. P. 2011, Report of the IAU working group on cartographic coordi-nates and rotational elements: 2009. Celestial Mechanics and Dynamical Astronomy 109, 101–135. Cavanaugh J. F., Smith J. C., Sun X., Bartels A. E., Ramos-Izquierdo L., Krebs D. J., McGarry J. F., The Mercury Laser Altimeter instrument for the MESSENGER mission, Space Sci. Rev. 131, p. 451-479, 2007 Kreslavsky, M. A., J. W. Head, G. A. Neumann, M. A. Rosenburg, O. Aharonson, D. E. Smith, and M. T. Zuber. (2013) Lunar topographic roughness maps from Lunar Orbiter Laser Altimeter (LOLA) data: Scale dependence and correlation with geologic features and units. Icarus, 2013, 226, 52-66. Mercury Dual Imaging System (MDIS) // Messenger. URL: http://www.messenger-education.org/instruments/mdis.php/
Keywords
Moon; Mercury; topographic roughness