observatory - Department
"Remote Sensing of Planets" (RSP)
(1) development of theoretical and experimental
models of light scattering in regolith-like media;
Basic results obtained in
(2) analysis of optical and radar data on planetary
surfaces obtained by earth-based telescopes and spacecrafts.
A new approach has been developed to study polarimetric
properties of the Moon at large phase angles, which makes it possible to
map the average regolith particle size for some regions of the nearside
of the Moon.
A theoretical model has been advanced for the negative
polarization of the light scattered by atmosphereless celestial bodies
at small phase angles; the model is based on the coherent enhancement of
Theoretical and computer models have been suggested
for the shadow and interference components of the phase dependence of brightness
of regolith-like surfaces; the models has been used for interpretation
of the data obtained by Clementine.
A theoretical model has been developed for spectral
albedo of multicomponent regolith-like surfaces with different types of
particle structure and composition; the model has been applied to the various
celestial bodies (The Moon, Phobos, and asteroids).
On the base of calculations and laboratory data,
an alternative explanation has been proposed to 3 micron absorption band
in low-resolution reflectance spectra of some asteroids: chemical trapping
of solar wind protons and formation of OH groups in the superficial zones
oxygen-bearing regolith particles; so the 3 micron absorption can take
place without presence of water molecules on the surface.
Laboratory simulations of Phobos spectra have shown
that its regolith particles can contain organic substance formed in solar
wind proton bombardment of carbonaceous material.
Fe, Ti and He3 (thermonuclear fuel)
abundance for the nearside of the Moon has been mapped; the first map of
lunar regolith maturity has been obtained.
On the base of Arecibo radar data as well as optical
data the first map of the regolith thickness has been obtained for the
nearside of the Moon.
Models of gravitational relaxation of the Maxwell
mountains (Venus) have been proposed; they explained the tectonic structure
distribution in this region observed by synthetic aperture radar on Magellan.
A method of measurements of height of small volcanoes
on the Venus surface imaged by Magellan radar has been developed, which
enabled an estimate of the thickness of volcanic plains for some regions
of the surface.
Using the data of laser altimeter on Mars Global
Surveyor, maps of roughness of the North hemisphere of the martian surface
have been obtained for the bases of 0.5 to 25 km.
A catalog of optical characteristics of lunar regions
has been compiled; the catalog includes photometric and polarimetric measurements
(the department researchers) and spectral data of C. Pieters (Brown
A unique laboratory device (photometer-polarimeter)
has been made for studies of light backscatter by surfaces of complex
structure at extremely small phase angles; numerous measurements with the
device constitute an experimental basis for testing theoretical models
of opposition enhancement of brightness and negative polarization of light
scattered by atmosphereless celestial bodies.
A new interpretation of the data of neutron spectrometer
on the Lunar Prospector has been given: the excess hydrogen detected near
the lunar poles can be explained by trapping of solar wind and galactic
protons on radiation defects, higher H content in polar regions being due
to lower escape probability at low temperature.
During the last 10 years the researchers of the
department defended six Ph. D theses and one dissertation of Doctor of
Science. Two Ph. D theses and two Doctor Sc. dissertations are in preparation.
Works of researchers of the department
were awarded by the State Prize of Ukraine (1986) and Barabashov Prize
of the Ukrainian National Academy of Sciences (1997).
Now the department works in close collaboration
including joint grants with many scientists, e.g.: C.
Pieters and J. Head (Brown University, USA ), R. Nelson (JPL,
USA), P. Helfenstein (Cornell University, USA), K.Muinonen and J. Piironen
(Helsinki Astronomical Observatory, Finland), G. Arnold and H. Hoffmann
(DLR, Germany), P.Pinet (Observatoir Midi-Pyrenees, France).