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Mapping of volatile and refractory
elements on the Moon
Alexey Andreyevich Berezhnoy
Sternberg Astronomical Institute, Moscow State University,
Moscow, Russia
EDUCATION Institution Location Degree Field YearMoscow State University Moscow, Russia Ph.D. Astrophysics Feb. 4, 1999Moscow State University Moscow, Russia M.S. Chemistry June 30, 1995Moscow State University Moscow, Russia B.S. Chemistry June 30, 1992
SCIENTIFIC EMPLOYMENTDepartment of lunar and planetary research, Sternberg Astronomical Institute, Moscow State University, Moscow, Russia, Senior Researcher, April 2013 – present Department of lunar and planetary research, Sternberg Astronomical Institute, Moscow State University, Moscow, Russia, Researcher, October 2001 – March 2013 Department of Chemistry and Chemical Biology, Rutgers University, New Jersey, USA, March 22, 2006 - March 19, 2007Advanced Research Institute for Science and Engineering, Waseda University, Tokyo, Japan, Postdoctoral Fellow, Sep. 30, 2002 – Sep. 29, 2004Instituto Nacional de Astrofisica, Optica y Electronica, Postdoctoral Fellow, Puebla, México, Oct. 1, 2001 – Sep. 30, 2002Department of lunar and planetary research, Sternberg Astronomical Institute, Moscow State University, Moscow, Russia, Researcher, Nov. 1997 – Oct. 2001Laboratory of Quantum Chemistry and Molecular Spectroscopy, Department of Chemistry, Moscow State University, Moscow, Russia, Junior Researcher, Nov. 1993 - June 1995
SKILLS
Thermochemical calculations of the equilibrium chemical composition of fireballs formed after collisions between comets and planets. Isotopic fractionation during impact processes.
Study of kinetics of chemical processes during impact events in the Solar system, in impact-induced lunar atmosphere, and volcanic eruptions on Io.
Petrologic mapping of the Moon based on Fe, Mg, and Al content.
Chemical treatment of Martian meteorites for mass spectroscopic analysis of theirs Be-10, Al-26, Ca-41, and Mn-53 radio nuclide content.
Radio observations of the Moon during impact events such as Lunar Prospector and SMART-1 impact, Leonid, and Perseid meteor showers.
Analysis of middle-resolution optical spectra of bright comets and Earth’s bolides.
Most perspective subjects for cooperation with KIGAM team
1. Analysis of KAGUYA GRS data1.1. Delivery of volatile species to the lunar poles. Interpretation of Kaguya observations regarding existence of hydrogen and sulfur at the Moon.
1.2. Application of petrological mapping technique to analysis of Kaguya maps of elemental abundances. Additional checking for instrumental mistakes. Search for rare rock types. Creation of high-resolution elemental maps, based on simultaneous analysis of Chandrayaan-1 M3 and Kaguya GRS data.
2. Preparation of scientific program of future lunar missions
2.1. Development of landing site selection procedure.
2.2. Estimation of required parameters of instruments for solving of most interesting scientific problems.
Clementine spacecraft showed the existence of permanently shadowed regions at north (left image) and south (right image) lunar polar regions.
1.1. Analysis of Kaguya GRS hydrogen and sulfur data
Detection of hydrogen at the poles of the Moon by Lunar Prospector
Lunar Prospector epithermal neutron counting rates map with surface relief maps of the lunar poles (Feldman et al., 1998).Mass of water ice in south polar regions of the Moon is estimated as 2*1014 g (Feldman et al., 2000).
• Lunar Prospector detected significant decrease of epithermal neutron counting rate over lunar poles (Feldman et al., 1998).
• These results are interpreted as existence of hydrogen at the poles of the Moon, probably, in the form of water ice (Feldman et al., 2001).
• Water ice mass fraction is estimated as 3-5 wt% in permanently shaded polar regions.
Kaguya gamma ray spectrometerKaguya gamma ray spectrometer has the following main parts:
– GRD (Gamma Ray Detector)– CDU (Cooler Driving Unit)– GPE (GRS-CPS Electronics)
Kaguya gamma ray spectrometer
Detector volume 252 cc, pure Ge Energy range 0.1 ~ 12 MeV Energy resolution 3 keV at 1.33 MeV Anticoincidence BGO, Plastic Scintillator system Size 600 mm×490 mm×415 mm Temperature 80-90 K Duration One year at 100 km altitude of the mission Spatial resolution 100 km Information transfer 6 kbps rate
Kaguya GRS simulated spectra at the H line region
Simulated Kaguya gamma ray spectrum. The accumulation time is 80 hours. The spectrum is calculated with the BGO anticoincidence mode and neglecting Compton scattering in the lunar regolith. S content is 0.5 wt%, H content is 200 ppm.
If Compton scattering in the lunar regolith is considered, then for 80 hours of observations it will be possible to detect 500 ppm H and 1 wt% S.
1:H2: S and O3:Mg
With use of SELENE GRS hydrogen can be detected during 300-500 hours of observations of regions poleward of 80 degrees.
Possibility of detection of carbon, sodium, and sulfur by gamma ray spectroscopy
• Carbon (1262, 3684, 4438, and 4945 keV ) is practically difficult to detect on the Moon due to interference with strong oxygen gamma ray lines having the same energy. The upper limit for C detection by GRS technique is about 1 wt % (Peplowski et al., in press).
• Sodium line at 440 kV can be detected at the poles of the Moon.
• Sulfur can be delivered to the Moon in the form of atomic sulfur or sulfur dioxide by impacts of comets and asteroids.
• Due to low evaporation rate sulfur and sodium can be stable in wider areas at the lunar poles in comparison with water ice.
• Sulfur line at 2230 keV has the interference with oxygen line. Another S line at 5421 keV is free from the interference with other lines.
Chemical composition of the fireball• Quenching of the chemical composition of the fireball occurs when
hydrodynamic and chemical time scales become comparable.
• Hydrodynamic time scale is equal to R/cs, where R is the comet radius, cs ~ 1 km/s is the sound speed at 2000 K.
• Chemical time scale is equal to ([X]k)-1, where k is the rate constant, [X] is the abundance of reactive molecule.
• Main reactions in the fireball are
H+H2O=H2+OH, H+CO2=OH+CO, H2+CO2= H2O+CO.
• For 1 km comet impact quenching of gas-phase reactions occurs at 1000 - 2000 K and 0.01 – 1 bar. However, catalysis of the chemical reactions on dust grains can significantly decrease quenching temperature and pressure.
The equilibrium chemical composition of adiabatically cooled fireball of cometary origin. The initial gas temperature is 5000 K, the initial pressure is 108 Pa, γ = 1.2.
PartialPressure
Gas-phase sulfur compounds are migrated to the temporary lunar atmosphere
• When the fireball temperature is below 1500 K, H2S is the main S-containing compound
• Fixation of sulfur into solid phase by reaction H2S + Fe = FeS + H2 is kinetically prohibited due to short hydrodynamic time scale (~ 1-10 s) during the fireball expansion
Chemical composition of impact-produced lunar atmosphere, formed by impact of an O-rich comet, versus time. The gas temperature is 300 K, the total surface number density is 1012 cm-3.
Surfacenumber density,
cm-3
Time, s
100 102 108104 106
Chemical composition of temporary lunar atmosphere after 107 s from the moment of creation of such an atmosphere versus
the total surface number density. The gas temperature is 300 K.
Surfacenumber density,
cm-3
Total surface number density, cm-3
Petrologic Mapping of the Moon
• We assume that all set of possible elemental abundances on the Moon can be explained by mixture of three end members rocks (ferroan anorthosites, troctolites, and mare basalts).
• Primary colors red, blue, and green are assigned for the end member classes mare basalts, ferroan anorthosites, and troctolites, respectively.
• The ternary space defined by these points is represented by the mixture of these primary colors.
1.2. Analysis of Kaguya GRS maps of abundances of main elements Si, O, Fe, Mg, Al, and Ca
Fe-Mg petrologic map of the Moon
North polar regions South polar regions
Equatorial regions
Scattergram shows LP data
in Fe-Mg compositional
space(Berezhnoy et al.,
2006)
Mg-Al petrologic map of the Moon
Equatorial regions
North polar regions South polar regions
Scattergram shows LP data
in Al-Mg compositional
space (Berezhnoy et al.,
2006)
Limitations of three end members hypothesis
• If three end members hypothesis is correct than colors of all pixels on both Al-Mg and Fe-Mg maps must be the same
• However, there are more green and red pixels on Al-Mg map than on Fe-Mg map• This can be explained by presence of other rock types as norites and
gabbronorites and by existence of errors in Lunar Prospector data
• Some rare rock types are present at South Pole Aitken basin
Lunar Prospector data in Mg-Fe-Al space with position of end-members.Distances from three-end member plane are negative in Th-rich western maria and
positive in far-side highlands Ca-rich, Al-poor small-area anomalies. Composition of western maria contradicts to composition of mare basalts
and KREEP basalts due to incorrect estimation of Mg and Si content in these regions by Lunar Prospector.
Fe, wt% Al, wt%
Mg,
wt%
Maps of distances of Lunar Prospector pixels
from the three end member plane in Mg-Al-Fe space
Dis
tanc
e, w
t%
MotivationLunar elemental abundance vs. multispectral data
Lunar Prospector gamma ray spectro-meter data: Al [wt%]
150 km resolution
Clementine UVVIS+NIR global mosaic
100 m resolution
Basic Idea: Mapping of UVVIS+NIR data to LP GRS data based on regression techniques
+60°
0°
-60°
+60°
0°
-60°-180° +180°0°
Wöhler, Berezhnoy, Evans: Estimation of Lunar Elemental Abundances 23
Global Mg-Fe petrologic map, based on joint analysis of Clementine VVIS+NIR and LP GRS data (Wohler et al., 2009)
R: Mare basaltG: Mg-suite rockB: Ferroan
Anorthosite
Three end-members Large-scale features of the map- Intuitive contrast between mare and highland regions- Strongly anorthositic farside highlands- Mg-rich soils in and around the Frigoris region- Cryptomaria (e. g. Schiller-Schickard, Balmer)
Estimation of olivine and pyroxene content
(b)
a – reflectance spectrum of the inner wall of the small fresh crater Bonpland ,b – continuum-removed spectrum of this crater.
FeO pyroxene, olivine, quenched glass
FeO (wt%) = 70.02×(BD2+0.56×NCSL2)-6.725
pyroxene, spinel, quenched glass
(a)
Wochler et al., Icarus, 235, 86-122, 2014
Study of mineral composition of the lunar regolith
Smoothed 3×3 continuum-removed reflectance spectra: • of the floor of Copernicus (M1 – M4),• the crater floor outside the melt (F1: small fresh crater; F2: mature surface),• the eastern central peak (CP), and flow structures A and B.
Wochler C. et al., Icarus, 235, 86-122, 2014
gg
Wöhler, Berezhnoy, Evans: Estimation of Lunar Elemental Abundances 26
Petrologic mapping, based on analysis of Clementine UVVIS+NIR and LP GRS data “Typical” and “exotic” soil types on small spatial scales (Wohler et al., 2009)
Tycho: Gabbroic/Mg-suite units Proclus: Highland crater
Mg Fe MgFe
Copernicus: Troctolitic central peaks Alphonsus: Pyroclastic deposits
Mg/AlMgFe
Tompkins et al. (1999)Lucey et al. (2002)
LeMouélic and Langevin (2001)Cohen and Pieters (2001)
Approaches, developed for joint analysis of LP GRS and infrared Clementine and Chandrayaan-1 M3 data, can be easy adopted for analysis of Kaguya GRS elemental maps.
Comparison of Lunar Prospector and Kaguya GRS
spectra (Hasebe et al., 2009)
Landing Sites of Previous Lunar Mission
(image is taken from http://www.bobthealien.co.uk/moonland3b.gif )
Chang’e 3
2. Preparation of scientific program of future lunar missions
Careful selection of landing site can be considered as a separate scientific task.For example, two international workshops were conducted in Space Research Institute (Moscow, Russia) in 2011 for performing of such a selection.
There are several aspects which must be solved for successful landing and operation on the lunar surface:
1) Technical possibility to perform landing in a selected point on the lunar surface;
2) Selected region must be flat enough for landing;
3) Selected region must be visible from Sun and Earth simultaneously during long period of time;
4) Selected regions must be attractive from scientific point of view.
List of proposed landing sites (taking into account study of elemental, mineral, and chemical composition of lunar regolith)
Proposed Region
Location on the Moon
Scientific tasks Required scientific
instruments
Communication with Earth
Solar illumination
2.1.1. Permanently Shadowed
Craters
80 S – 90 S,80 N – 90 N
Study of volatile species such as H2O, CO, CO2, NH3, PH3,
and amino acids
Infrared spectroscopy, mass spectroscopy, XRS
Only via lunar orbiter, risky for landing at big landing eclipses
Absent. Instruments must be able to work at 40 K and use own
energy sources
2.1.2. Illuminated Lunar Polar
Regions
80 S – 90 S,80 N – 90 N
Study of OH – containing minerals, Na, Mg, and Ca at
the surface
Infrared and optical spectroscopy, mass spectroscopy, XRS
Very difficult without lunar orbiter, risky for landing at big landing
eclipses
During limited period of the lunation, Sun is
very low above horizon
South Pole Aitken basin
15 S - 90 S,130 E – 130 W
Unusual rocks from upper mantle
Infrared spectroscopy, XRS
Difficult without lunar orbiter
Sun is low above horizon
2.1.3. Pyroclastic
deposits
Gassay Lussac N (13 N, 21 W)
Unusual rocks, OH-containing minerals
Infrared spectroscopy, XRS
Easy Suitable
List of proposed landing sites (taking into account study of elemental, mineral, and chemical composition of lunar regolith)
Proposed Region Location on the Moon
Scientific tasks Required scientific
instruments
Communication with Earth and roughness
Solar illumination
Reiner-gamma formation
7.5 N, 59 W Search for magnetic anomalies and traces of
recent comet impact
Magnetometer, mass spectrometer
Easy Suitable
Aristarchus crater 24 N, 47 W Search for volcanic activity on the Moon
Alpha particle, mass and infrared
spectroscopy
Easy, risky for landing at big landing eclipses
Suitable
Central peak of Tycho crater
43 S, 11 W Search for troctolites XRS Easy, risky for landing Suitable
Olivine-rich regions
25 N, 65 W Search for olivine Infrared spectroscopy,
XRS
Easy, risky for landing at big landing eclipses
Suitable
Mare Frigoris 60 N, 0–30 E
Search for aluminous mare basalts
Infrared spectroscopy,
XRS
Not very difficult, risky for landing at big
landing eclipses
Suitable
Thermal stability of different species at the poles of the Moon
(http://science.nasa.gov/science-news )
LCROSS impact on the Moon (http://lcross.arc.nasa.gov )
After LCROSS impactH2O, CO, H2, Ca, Hg, Mg (Gladstone et al., 2010), H2O, H2S, NH3, SO2, C2H4, CH3OH, CH4, OH (Colaprete et al., 2010), and Na
(Killen et al., 2010)were detected
in the LCROSS impact plume.These species may be delivered
to the poles of the Moon by impactsof comets, asteroids, and meteoroids.
Na
S
Hg
H2O
Mg
2.1.1. Permanently Shadowed Lunar Polar Regions
Compound Content in the LCROSS cloud
Content at the poles, wt%
Mass at the poles, kg
Content in comets
Main source O-comets, kg/year
Asteroids, kg/year
C-comets, kg/year
Low-speed comets, kg/year
H2O 100 5,6 1013 100 Asteroids 105 2×106 4×10-3 2×104
CO 15 0,08 5×108 10 C, О- comets, asteroids
2×105 2×105 2×105 2×103
CO2 2,17 0,04 2×1010 5 Asteroids 105 1,5×106 0,02 4×103
CH3OH 1,55 0,1 2×1011 0,2-6 Low-speed comets
2×10-7 2×10-8 4×10-8 4×102
CH4 0,65 0,003 2×108 0,2-1,5 C- comets 10-2 2×10-4 2×104 70
C2H4 3,12 0,02 2×109 0,3 C- comets 10-9 10-13 104 60
H2S 16,75 0,2 4×1010 0,12-0,6 Asteroids 5×103 105 0,02 30
SO2 3,19 0,2 1011 0,1 Asteroids 3 2×104 10-18 30
NH3 6,03 0,07 5×1010 0,1-1,6 Low-speed comets
0,2 0,1 0,01 60
Origin of volatile compounds at the poles of the Moon (Berezhnoy et al., 2012)
Image of the Moon taken by the Chandrayaan-1 Moon Mineralogy Mapper (Pieters et al., 2009). Blue shows the spectral signature of hydroxide, green shows the brightness of the surface as measured by reflected infrared radiation from the Sun and red shows a mineral called pyroxene.
2.1.2. Illuminated Lunar Polar Regions – Enriched content of OH, Na, Mg, and Ca in the regolith
Chemistry of collisions of meteoroids with planets
Typical sizes and velocities of impactors are 0.1-1 cm and 30-60 km/s.
Adiabatical expansion of the fireball T0/T = (P0/P) ( -1)/ , where the initial temperature T0 = 104 K,
The initial pressure P0 = 104 bar, and = 1.2.
1) High temperature and pressure in the impact-produced fireball – chemical reactions occur quickly and the chemical composition is in the equilibrium
2) Cooling of the fireball leads to quenching of the chemical composition of the fireball
3) Low temperature and pressure – no collisions and no reactions in the fireball
Equilibrium fraction of gas-phase Na, K, Ca-containing species versus temperature during the fireball cooling. The initial temperature is 104 K, the initial pressure is 104 bar, γ = 1.2. The mass ratio of matter of planetary and CI meteorite origin is taken to be 30:1.
2000 2500 3000 3500 4000 4500 5000 5500-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
100101 P, bar
Ca(OH)2
Na2 KO
Na2O
KCaOH
KOH
CaCaO
NaO
NaOH
Na
Log
arith
m o
f re
lativ
e ab
unda
nce
T, K
No reactions Quenching Equilibrium
Equilibrium fraction of gas-phase Si, Fe, Mg, Al-containing species versus temperature during the fireball cooling. The initial temperature is 104 K, the initial pressure is 104 bar, γ = 1.2. The mass ratio of matter of planetary and CI meteorite origin is taken to be 30:1.
2500 3000 3500 4000 4500 5000 5500-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
30 10010 P, bar
Mg(OH)2
MgOH Mg
Fe
AlOH
AlO2
AlMgO
SiO2 AlO
SiO
Log
arith
m o
f re
lativ
e a
bun
dan
ce
T, K
No reactions Quenching Equilibrium
Neutron flux evaluation in Fra Mauro LPD region (Berezhnoy et al., COSPAR
meeting, 2014)
The distribution of epithermal neutron (0.3 eV – 500 keV) flux across the entire of lunar surface
according LEND.
The distribution of hydrogen (anti correlates with EN) according LPNS.The resolution of both maps is 0.5x0.5 degrees, penetration depth is about 1 m.
2.1.3. Lunar Pyroclastic Deposits
Comparison between smoothed topographicallyand thermally corrected Chandarayaan-1 M³ spectra
LPD
Fra Mauro crater floor
OH absorption depth is larger for the LPD
M³ image at 1579 nm
Topographically corrected Chandrayaan-1 M³ reflectance at 1579 nm
Image is taken from Berezhnoy et al. (COSPAR meeting, 2014).
0.05
0.17
Hydroxyl absorption depth (R2657 / R2817 ratio).
Image is taken from Berezhnoy et al. (COSPAR meetig, 2014).
1.01
1.06Chandrayaan-1 M³-based surface temperature estimation:
Positive anomalies of the hydroxyl absorption depth for the darkest parts of the LPD
Most perspective subjects for cooperation
1. Analysis of Kaguya GRS data1.1. Delivery of volatile species to the lunar poles. Interpretation of Kaguya observations regarding existence of hydrogen and sulfur at the Moon.
1.2. Application of petrological mapping technique to analysis of Kaguya maps of elemental abundances. Additional checking for instrumental mistakes. Search for rare rock types. Creation of high-resolution elemental maps, based on simultaneous analysis of Chandrayaan-1 M3 and Kaguya GRS data.
2. Preparation of scientific program of future lunar missions
2.1. Development of landing site selection procedure.
2.2. Estimation of required parameters of instruments for solving of most interesting scientific problems.