RSP
lunar data
Icarus 137, 222-234 (1999) Article ID icar.l999.6046,
available online at http://www.idealibrary.com
Iron
and Titanium Abundance and Maturity Degree
Distribution
on the Lunar Nearside
Yurij G.
Shkuratov, Vadym G. Kaydash, and Nickolaj V. Opanasenko
Astronomical
Observatory of Kharkov State University, Sumskaya Street 35, Kharkov 310022,
Ukraine
E-mail:
shkuratov@ygs.kharkov.ua
Received
April 10,1998; revised September 3,1998
New digital images of the lunar nearside albedos at 0.42, 0.65, 0.75,
and 0.95 mm derived from telescopic data were
used to map the abundance and distribution of iron, titanium, and maturity
degree on the lunar nearside. Developing the approach by P. Lucey et al.
(1995, Science 268, 1150), a method of separating contributions of the
Fe and Ti abundance and maturity degree to spectral properties of the lunar
surface is presented. The main objective of the method is an analysis of
the 3D correlation diagram of optical characteristics of regolith material
with the aim of choosing a coordinate system providing the best correlations
of these characteristics with Fe and Ti abundance (data for the Surveyor,
Luna, and Apollo landing sites) and with maturity degree (laboratory measurements
of lunar samples by E. Fischer and C. Pieters (e.g., 1996, J. Geophys.
Res. 101, 2225). To find the coordinates, a geometrical optics model of
light scattering in particulate media enabling to calculate the absorption
coefficient from albedo measurements is used. An analysis of the correlation
diagram FeO-TiO2; provides two maps characterizing optical types
of the lunar nearside. In particular, the maps show that the basalts of
Mare Serenitatis and Mare Tranquillitatis are not widely extended on the
lunar nearside. The maturity degree, parameter Is/FeO, was also
mapped. Regions with Is/FeO£
50 are young craters surrounded by ray systems, whereas the condition Is/FeO³70
corresponds to regions associated with Copernicus ejecta, western boundaries
of Mare Tranquillitatis and Mare Serenitatis, and a portion of the south
highland. The new map of FeO distribution on the lunar nearside was used
to study a correlation between iron content and distribution of remanent
magnetism over the lunar surface. The relationship obtained has a reverse
behavior: the lower the iron content, the higher the magnetism. ©
1999 Academic Press
Key Words: lunar nearside; optical characteristics of regolith;
maturity degree; Fe and Ti abundance.
Press here to download a full zipped MS
WORD6.0/95 version of this article (size=2420 kb) or
MS WORD6.0/95 version without
pictures (size=26 kb)
Digital images of albedo of the lunar
nearside are now!
Here you can download zipped images of albedo
at :
All images stored in raw graphic format "IZIUM" (*.iz extension), developed
by Dmitrij G. Stankevich.
Here you can find description
of IZIUM format and details of projection
and coordinate system of albedo images.
Icarus 137,235-246 (1999) Article ID icar. 1998.6035,
available online at http://www.idealibrary.com
A
Model of Spectral Albedo of Particulate Surfaces: Implications for Optical
Properties of the Moon
Yurij Shkuratov
and Larissa Starukhina
Astronomical
Observatory, Kharkov State University, Sumskaya St., 35, Kharkov, 310022,
Ukraine
E-mail:
shkuratov@ygs.kharkov.ua
and
Harald Hoffmann
and Gabriele Arnold
Institute
of Planetary Exploration, German Aerospace Center (DLR), Rudower Chaussee
5, D-124S9 Berlin, Germany
Received
September 9, 1997; revised June 29, 1998
A simple one-dimensional geometrical-optics model for spectral albedo
of powdered surfaces, in particular of lunar regolith, is presented. As
distinct from, e.g., the Kubelka-Munk formula, which deals with two effective
parameters of a medium, the suggested model uses spectra of optical constants
of the medium materials. Besides, our model is invertible, i.e., allows
estimations of spectral absorption using albedo spectrum, if a priori data
on the real part of refractive index and surface porosity arc known. The
model has been applied to interpret optical properties of the Moon. In
particular, it has been shown that: (1) both color indices and depth of
absorption bands for regolith-like surfaces depend on particle size, which
should be taken into account when correlations between these optical characteristics
and abundance of Fe and Ti in the lunar regolith are studied; (2) fine-grained
reduced iron occurring in regolith particles affects band minima positions
in reflectance spectra of lunar pyroxenes and, consequently, affects the
result of determination of pyroxene types and Fe abundance by Adams' method.
© 1999 Academic Press
Press here to download a full zipped MS
WORD 97 version of this article (size=1487 kb) or
MS WORD 97 version without pictures
(size=42 kb)
ICARUS 95, 283-299 (1992)
Polarimetric
and Photometric Properties of the Moon:
Telescopic
Observations and Laboratory Simulations
1.
The Negative Polarization
Yu. G. SHKURATOV,
N. V. OPANASENKO, and M. A. KRESLAVSKY
Astronomical
Observatory, Kharkov Slate University, 35 Sumskaya St., 310022 Kharkov,
Ukraine, USSR
Received
April 8, 1991; revised December 6, 1991
In 1985-1990 a wide program of photometric and polarimetric observations
of the Moon was carried out by means of a new spectropolarimeter which
made possible an accuracy of polarimetric measurements up to 0.04%. In
order to interpret these and other observations, laboratory photometric
and polarimetric measurements of some natural and artificial samples have
been made. In the first part of this paper results of linear and parabolic
regression analysis for parameters of the negative polarization and photo-metric
characteristics of the Moon are presented. A principal component analysis
was also carried out. Only two statistically significant principal components
were found; the first is predominantly determined by alhedo and the second
is controlled by some parameters of the negative polarization. Some relationships
between polarimetric and photometric parameters are studied in detail.
In particular, a two-branch dependence of polarization degree in the minimum
Pmin vs. albedo A was discovered for both telescope and
laboratory measurements. A correlation between Pmin and the
slopes of brightness phase curves at small phase angles was found. It points
out a common origin of the negative polarization and the opposition effect.
Correlations were found between some color ratios of polarimetric parameters
and the color index (0.65 mm/0.42 mm).
For instance, on a log-log scale there is a linear dependence of the color
ratio of the slopes of polarization phase curves at the inversion angles
upon the color index. This contradicts the asteroid polarimetric Q-effect
(B. Zeilner and J. Gradie, 1976, Astron. J, 81, 262-280). ©
1992 Academic press, Inc.
ICARUS 99, 468-484 (1992)
Polarimetric
and Photometric Properties of the Moon: Telescope Observation and Laboratory
Simulation
2.
The Positive Polarization
Yu. G. SHKURATOV
and N. V. OPANASENKO
Astronomical
Observatory of Kharkov State University, Sumskaya Street, 35, Kharkov 310022,
USSR
Received
September 9, 1991; revised February 7, 1992
This article is a sequel to Shkuratov et al. (1992, Icarus 95, 283-299).
It considers the lunar positive polarization based on telescopic observations
and laboratory measurements. Data obtained from point-by-point measurements
as well as from images are used to study the Moon at phase angles near
the polarization maximum. The first type of data shows that measurements
corresponding to young craters deviate from the regression line of the
log A — log P correlation (A and P are the
reflectance and polarization degree, respectively). Following the approach
suggested by Shkuratov et al. (1980, Astron. Circ. 1112, 3), new images
of the polarimetric anomaly parameter characterized by b = log A
+ a • log Pmax are obtained for the western part
of the lunar disc. Young mare and highland craters show up. Some anomalies
presumably can be identified as volcanic ash deposits. A new empirical
relationship between b and particle size was established by laboratory
measurements of the lunar samples supplied by the "Luna" space probes.
This relationship as well as that presented by Geake and Dollfus (1986,
Mon. Not. R. Astron. Soc. 218, 75) is not universal and should be used
carefully. New parameters (width and asymmetry) of the positive polarization
branch, d = (a1
- a2)/amax
and D = (amax
- a1)/(a2
- amax), where a1
and a2 are the phase angles at which
P = 0.7 • Pmax, are introduced. From laboratory
polarimetric measurements of artificial glasses and lunar samples, some
correlations between these parameters and the particle size of the surface
were established. © 1992 Academic press, inc.
Digital images of polarimetric parameters
of the lunar nearside are now!
Here you can download zipped images of
albedo at :
A.ZIP (268 kb) - B
= disk brightness distribution at l=0.42 mm,
%*1000
B.ZIP (265 kb) -
A = equigonal albedo, %*1000
C.ZIP (238 kb) -
P = polarization degree, %*100
D.ZIP (271 kb) -
Q = second Stokes parameter Q=A*P, %*%*100
E.ZIP (218 kb) -
d = particle size, microns*100
F.ZIP (216 kb) -
dc = particle size corrected by releif, microns*100
Here you can find description
of IZIUM format in which images are stored
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