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We have attempted to constrain the lunar core size from electrical conductivity sounding by using magnetic field data from the Kaguya (KG) and Lunar Prospector (LP) satellites. As suggested by previous studies, the signature of induction in the core can sometimes be detected by the satellites as an internal dipole field when the Moon enters from the magnetosheath to the tail lobe of the Earth’s magnetosphere...
We present results of the highest-resolution simulations to date of potential Moon-forming impacts using a Lagrangian, particle-based method (smooth particle hydrodynamics, or SPH) and an Eulerian, grid-based method with adaptive mesh refinement (AMR-CTH). We consider a few candidate impacts advocated by recent works, directly comparing simulations performed at varying resolutions and with both numerical...
Schrödinger Basin provides a window into the stratigraphy of the lunar crust adjacent to the South Pole-Aitken Basin region that we have probed with Lunar Reconnaissance Orbiter, Moon Mineralogy Mapper (M 3 ), and crater-scaling relationships. The composition of materials that make up the basin wall, impact melt, and peak ring provide a cross-section of the lunar crust, which reveals products...
Precession of the orbit poles and spin poles for triaxial bodies, including the possibility of phase locking, is addressed here. We provide a simple derivation of the time-averaged gravitational potential and associated torque, thereby confirming the results of Gladman et al. (Gladman, B., Quinn, D., Nicholson, P., Rand, R. [1996]. Icarus 122, 166–192).
Saturn is orbited by a half dozen ice rich middle-sized moons (MSMs) of diverse geology and composition. These comprise ∼4.4% of Saturn’s satellite mass; the rest is Titan, more massive per planet than Jupiter’s satellites combined. Jupiter has no MSMs. Disk-based models to explain these differences exist, but have various challenges and assumptions. We introduce the hypothesis that Saturn originally...
Lunar basin-forming impacts produce enormous volumes (>10 5 km 3 ) of impact melt. All known basin-forming impacts combined may produce ∼10 8 km 3 of impact melt, ∼1/20th the volume of the lunar crust. Despite their volumetric importance, the geology and petrology of massive deposits of impact melt on the Moon have been little studied, in part because most basin...
Near-InfraRed (NIR) data obtained at the Moon by the SIR-2 instrument aboard Chandrayan-1 have been analyzed and classified according to their spectral absorption characteristics. This approach yielded a new NIR map, based on 10 spectral categories that we have identified, which cover a substantial portion of the lunar nearside. The inferred distribution of materials that share similar reflectance...
The Moon spends 20% of its orbit within the terrestrial magnetosphere. During this time it experiences a flux of ions from the Earth, which can be accelerated within the magnetosphere prior to impacting the Moon. Both 3D multi-fluid simulations and particle tracking were used to study the lunar environment while the Moon is inside the magnetosphere and quantify the energy and flux of ionospheric ions...
We report on our analysis of twilight observations of the lunar atmosphere as observed by the LAMP instrument aboard NASA’s Lunar Reconnaissance Orbiter. Using data collected between September 2009 and March 2013, we have examined over 7.7millions of integration time obtained when the surface was in darkness, but the atmosphere between the spacecraft and the surface was in sunlight. Using these data,...
Remote-sensing datasets obtained by each instrument aboard Selenological and Engineering Explorer (SELENE) and Chandrayaan-1 have not been compared directly, and the characteristics of each instrument’s data, which may reflect the observation conditions of each instrument and/or residual error in instrument calibration, are unknown. This paper describes the basic characteristics of the data derived...
Based on the equilibrium thermochemical approach and quenching theory, the formation of Na-, K-, Li-, Si-, Ca-, Al-, Mg-, and Fe-bearing molecules and dust particles in impact-produced clouds formed after collisions between meteoroids and the Moon is considered. Photolysis lifetimes and energies of photolysis products of oxides and hydroxides of the main elements are estimated. The estimated fraction...
The Orientale basin is the best-preserved multi-ring impact basin on the Moon, spanning ∼900km in diameter at its outermost ring. It consists of three concentric ring structures known as the Inner Rook, Outer Rook, and Cordillera. Based on geologic and topographic evidence, the Cordillera ring has been interpreted as forming through listric normal faulting from the inward collapse of the interior...
Several modern optical instruments orbited the Moon during 2008 and 2009 onboard the SELENE and Chandrayaan-1 spacecraft and provided a welcomed feast of spectroscopic data to be used for scientific analyses. The different spatial and spectral resolutions of these sensors along with diverse illumination geometry during data acquisition make each set of data unique, and each instrument contributes...
This study presents the development and implementation of an algorithm for automatic detection, classification and contextual information such as ejecta and the status of degradation of the lunar craters using SELENE panchromatic images. This algorithm works by a three-step process; first, the algorithm detects the simple lunar craters and classifies them into round/flat-floor using the structural...
We report on the detection of H2 as seen in our analysis of twilight observations of the lunar atmosphere observed by the LAMP instrument aboard NASA’s Lunar Reconnaissance Orbiter. Using a large amount of data collected on the lunar atmosphere between September 2009 and March 2013, we have detected and identified, the presence of H2 in the native lunar atmosphere, for the first time. We derive a...
Galactic cosmic rays are a potential energy source to stimulate organic synthesis from simple ices. The recent detection of organic molecules at the polar regions of the Moon by LCROSS (Colaprete, A. et al. [2010]. Science 330, 463–468, http://dx.doi.org/10.1126/science.1186986), and possibly at the poles of Mercury (Paige, D.A. et al. [2013]. Science 339, 300–303, http://dx.doi.org/10.1126/science...
Our knowledge about the lunar environment is based on a large volume of ground-based, remote, and in situ observations. These observations have been conducted at different times and sampled different pieces of such a complex system as the surface-bound exosphere of the Moon. Numerical modeling is the tool that can link results of these separate observations into a single picture. Being validated against...
High-resolution images of the Surveyor, Luna, and Apollo landing sites obtained by the Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) show regions around the landers where reflectivity of the surface was modified. We interpret the change in reflectance properties of these regions mainly as disturbance of the regolith by rocket exhaust during descent of the spacecraft and we refer...
We present the first direct laboratory measurement of vapor produced by simulated micrometeoroid bombardment. New in situ observations from the Mercury Surface, Space Environment, Geochemistry and Ranging (MESSENGER) spacecraft, and the anticipation of results from the Lunar Atmosphere and Dust Environment Explorer (LADEE), have highlighted the uncertainty surrounding the role of micrometeoroid impacts...
Characteristics of impact basins are important fundamental knowledge for assessing basin forming impacts and their influence on surficial and interior structural evolutions for lunar and planetary bodies. To estimate impact basin characteristics based on spherical harmonic expressions of topographic figures, we propose a quantitative method that we apply it to actual lunar topographic data. The estimated...
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