Three Chandrayaan-I related papers out

Note: I wrote this on my earlier blog hosted as http://parallelspirals.blogspot.com. I recovered the text from the WayBack Machine. This post appeared on February 23, 2011 as per the time stamp. I’m trying to collect here again all my old writings spread on various blogs.

Three papers directly related to instruments on-board the Chandrayaan-I spacecraft are out in 2011. Here’s a brief pointer to each.

1. Goldschmidt crater and the Moon’s north polar region: Results from the Moon Mineralogy Mapper (M3); Cheek, Pieters et. all

2. Strong influence of lunar crustal fields on the solar wind flow [full paper – PDF]; Charles Lue et. all

3. Lithological mapping of central part of Mare Moscoviense using Chandrayaan-I Hyperspectral Imager (HySI) data; S Bhattacharya et. all

For the first paper, Cheek et. all, have trained their eyes on the Goldschmidt crater. The comparison of spectroscopic details from Goldschmidt to the Moon Mineralogy Mapper (M3)’s data of the Northern pole and from three different regions provide three different soil types – feldspathic soils with a low-Ca pyroxene component, feldspathic soils and basaltic soils. The content of Goldschmidt is feldspathic and was found to be locally different from the surrounding highlands. They state that the water spectrum is closely associated with the mineralogy of where the spectrum is located. Goldschmidt is said to have higher concentration of water spectrum compared to the local highlands but is similar to the feldspathic soil in the lunar far side.

The second paper by Charles Lue et all is available in full. The SARA payload on Chandrayaan-I had detected the presence of mini-magnetospheres on the surface of the Moon. The paper Lue et. all believes that these magnetospheres affect the upstream solar winds. This affect the rate of solar wind proton hitting the surface of the Moon and also perhaps space weathering in places near the magnetic anomalies. The team uses data from the Solar Wind Monitor (SWIM) on Chandrayaan-I for these studies. Concluding, they say:

Magnetized electrons are deflected by the magnetic field gradient and set up a charge separation (because  protons are non‐magnetized), resulting in an ambipolar  electric field. The related potential repels a fraction of the  protons. Therefore, the deflection can take place not only  over the strongest magnetic anomalies where the protons can  be magnetized, but (although at a lower efficiency) also at  weak, isolated anomalies of ❤ nT at 30 km altitude, with a  width of <100 km. Similar charge separation scenarios have  been discussed in early studies based on Apollo 12 surface  observations [e.g., Neugebauer et al., 1972], and in a recent  review paper by Halekas et al. [2010].

This paper too has some influence on the lunar water formation technique suggested of solar wind implanting protons which are used by the OH ions to form water:

Regardless of the deflection mechanism for protons,  the high solar wind deflection and reflection rates, as ions  and neutral atoms, imply a lower proton implantation rate in  the regolith at magnetic anomalies that may alter the space  weathering compared to the surrounding areas. Moreover, it  might affect the production of OH/H2O in the outermost  layer of the regolith via transfer of solar wind‐implanted  protons to the mineral‐bound oxygen [Pieters et al., 2009].

The paper is available here in full.

The third paper, Bhattacharya et all investigated the central region of the Mare Moscoviense region of the Moon. The paper has identified 5 geological units:

five major compositional units have been identified: highland basin soils, ancient mature mare, highland contaminated mare, buried unit with abundant low-Ca pyroxene (LCP), and youngest mare unit

The paper seems to be aimed as basis of using the Hyper Spectral Imager (HySI) data to delineate major compositional structures on the surface of the Moon and has done so successfully enabling it to be used for the rest of the data sets obtained.

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