Search Publications
Deducing Lunar Regolith Porosity From Energetic Neutral Atom Emission
Wurz, P.; Galli, A.; Jäggi, N. +6 more
The porosity of the upper layers of regolith is key to the interaction of an airless planetary body with precipitating radiation, but it remains difficult to characterize. One of the effects that is governed by regolith properties is Energetic Neutral Atom (ENA) emission in the form of reflected and neutralized solar wind protons. We simulate this…
First Observation of Transport of Solar Wind Protons Scattered From Magnetic Anomalies Into the Near Lunar Wake: Observations by SARA/Chandrayaan-1
Barabash, Stas; Holmström, Mats; Futaana, Yoshifumi +5 more
We report the first observational evidence for the transport of the solar wind protons scattered from the lunar magnetic anomaly (LMA) into the near wake region from SWIM/Sub-keV Atom Reflecting Analyzer (SARA) aboard Chandrayaan-1. These protons with high angular spread are observed in the near wake region for specific orientations of interplanet…
New suprathermal proton population around the Moon: Observation by SARA on Chandrayaan-1
Barabash, Stas; Holmström, Mats; Futaana, Yoshifumi +4 more
We report a new population of suprathermal H+ (∼1.5-3 times the solar wind energy) around the Moon observed by Solar Wind Monitor (SWIM)/Sub-keV Atom Reflecting Analyzer (SARA) on Chandrayaan-1. These ions have large initial velocity (>100 km s-1) and are observed on the dayside, near the terminator, and in the near-wake r…
On the origin of the ionosphere at the Moon using results from Chandrayaan-1 S band radio occultation experiment and a photochemical model
Choudhary, R. K.; Bhardwaj, Anil; Dhanya, M. B. +2 more
The origin of the Moon's ionosphere has been explored using Chandrayaan-1 radio occultation (RO) measurements and a photochemical model. The electron density near the Moon's surface, obtained on 31 July 2009 (∼300 cm-3), is compared with results from a model which includes production and recombination of 16 ions, solar wind proton charg…
In situ optical measurements of Chang'E-3 landing site in Mare Imbrium: 1. Mineral abundances inferred from spectral reflectance
Xiao, Long; Di, Kaichang; Yuan, Ye +11 more
The visible and near-infrared imaging spectrometer on board the Yutu Rover of Chinese Chang'E-3 mission measured the lunar surface reflectance at a close distance (~1 m) and collected four spectra at four different sites. These in situ lunar spectra have revealed less mature features than that measured remotely by spaceborne sensors such as the Mo…
Remote energetic neutral atom imaging of electric potential over a lunar magnetic anomaly
Barabash, S.; Futaana, Y.; Wurz, P. +5 more
<title type="main">Abstract<p label="1">The formation of electric potential over lunar magnetized regions is essential for understanding fundamental lunar science, for understanding the lunar environment, and for planning human exploration on the Moon. A large positive electric potential was predicted and detected from single point mea…
Proton entry into the near-lunar plasma wake for magnetic field aligned flow
Barabash, S.; Futaana, Y.; Wurz, P. +7 more
We report the first observation of protons in the near-lunar (100-200 km from the surface) and deeper (near anti-subsolar point) plasma wake when the interplanetary magnetic field (IMF) and solar wind velocity (vsw) are parallel (aligned flow; angle between IMF and vsw≤10°). More than 98% of the observations during aligned fl…
Strong influence of lunar crustal fields on the solar wind flow
Barabash, Stas; Holmström, Mats; Futaana, Yoshifumi +5 more
We discuss the influence of lunar magnetic anomalies on the solar wind and on the lunar surface, based on maps of solar wind proton fluxes deflected by the magnetic anomalies. The maps are produced using data from the Solar WInd Monitor (SWIM) onboard the Chandrayaan-1 spacecraft. We find a high deflection efficiency (average ∼10%, locally ∼50%) o…
Compositional diversity at Theophilus Crater: Understanding the geological context of Mg-spinel bearing central peaks
Head, J. W.; Dhingra, D.; Pieters, C. M. +3 more
Analysis of high resolution Moon Mineralogy Mapper (M3) data reveals the presence of a prominent Mg-spinel-rich lithology in the central peaks of Theophilus crater on the lunar nearside. Other peak-associated lithologies are comprised of plagioclase, olivine, and pyroxene-bearing materials. A consistent spatial association of Mg-spinel …
Scattering function for energetic neutral hydrogen atoms off the lunar surface
Barabash, S.; Holmström, M.; Futaana, Y. +7 more
The Sub-keV Atom Reflecting Analyzer instrument on board the lunar orbiter Chandrayaan-1 provided a large number of measurements of lunar energetic neutral atoms (ENAs). These ENAs were formerly solar wind ions, which were neutralized and backscattered from the lunar surface. The angles under which the ENAs are scattered strongly depend on the sol…