Lunar nitrogen: Secular variation or mixing?

The two current models to explain the nearly 40% variation of the lunar nitrogen isotopic composition are: (1) secular variation of solar wind nitrogen; and (2) a two component mixing model having a constant, heavy solar wind admixed with varying amounts of indigenous light lunar N (LLN). Both models are needed to explain the step pyrolysis extraction profile. The secular variation model proposes that the low temperature release is modern day solar wind implanted into grain surfaces, the 900 C to 1100 C release is from grain surfaces which were once exposed to the ancient solar wind but which are now trapped inside agglutinates, and the >1100 C release as spallogenic N produced by cosmic rays. The mixing model ascribes the components to solar wind, indigenous lunar N and spallogenic N respectively. An extension of either interpretation is that the light N seen in lunar breccias or deep drill cores represent conditions when more N-14 was available to the lunar surface

The Holbrook Meteorite - 99 Years Out in the Weather

At 7:15pm on the evening of 19th July 1912, a bright fireball appeared in the sky above Navajo County, Arizona [1]. After several loud detonations, approximately 16,000 mostly pea-sized stones fell near the Arntz siding of the Santa Fe Railroad, 7 miles from the town of Holbrook. A search orchestrated by W.M.Foote resulted in nearly 220 kg of material being recovered; samples were exchanged with a great many of the World's Museums [2]. In 1931 Harvey Nininger revisited the site and was able to find another 23 kg that had originally been missed [3]. One of us (EKG) returned again in 1968 and found a further ca 1.5 kg specimen [4]. Meteorite hunters have been going back to Holbrook ever since in the hope of more finds. For example in 2001 a group of 45 searchers accumulated 440 g of previously overlooked L6 group meteorite fragments. In 2011, the 99th anniversary of the event, Rubin Garcia located 11 mini-meteorites [5]

The exposure history of the Apollo 16 site: An assessment based on methane and hydrolysable carbon

Nineteen soils from eight stations at the Apollo 16 landing site have been analyzed for methane and hydrolysable carbon. These results, in conjunction with published data from photogeology, bulk chemistry, rare gases, primordial and cosmogenic radionuclides, and agglutinate abundances have been interpreted in terms of differing contributions from three components-North and South Ray Crater ejecta and Cayley Plains material

Revised target co-ordinates for the Beagle 2 lander

The revised, IAU 2000 target co-ordinates of the Mars Beagle 2 lander are 11.6oN, 90.75oE

Pyrolysis-GC×GC-TOFMS to characterize carbonaceous chondrites

Using pyrolysis-GCxGC-TOFMS to analyze organic carbon in carbonaceous chondrites gives a massive increase in both sensitivity and structural information from samples when compared to traditional Py-GC-MS

The metabolism of methyl methanesulphonate

Methyl methanesulphenate has been prepared labelled with radioactive carbon and its metabolism studied in rat, mouse and rabbit. The distribution of the drug after injection has been determined in the rat. Quantitative studies in this species have shown that less than as % of the injected drug is excreted or exhaled in 24 hours. Assay of tissue levels of radioactivity after injection has confirmed that the majority of the drug remains bound within the animal body. In the rat, the principal metabolic reaction has been shown to take place in the liver with glutathione. The S-methylglutathione formed is excreted in bile and this intermediate was the source of the urinary metabolites. In the urine, conjugates of S-methylcyateine and S-methylthioglycollic acid, together with small quantities of radioactive urea, have been recognized. The main metabolite has not been identified but appears to be a substituted guanidine compound. The possible significance of these results of these results has been discussed in terms of sell biochemistry

The Apollo Virtual Microscope Collection: Lunar Mineralogy and Petrology of Apollo 11, 12, 14, 15 and 16 Rocks

We report on the new Virtual Microscopes on Apollo 16 lunar samples in our Apollo Virtual Microscope collection

A hydrogen isotope study of CO3 type carbonaceous chondrites; comparison with type 3 ordinary chondrites

Meteorites of the Ornans type 3 carbonaceous chondrites exhibit a range in degree of equilibration, attributed to differing amounts of thermal metamorphism. These differences have been used to split the CO3 chondrites into petrologic sub-types from 3.0, least equilibrated, to 3.7, being most equilibrated. This is similar to the system of assigning the type 3 ordinary chondrites into petrologic sub-types 3.0 to 3.9 based upon thermoluminescence (TL) and other properties; however, the actual range of thermal metamorphism experienced by CO3 chondrites is much less than that of the type 3 ordinary chondrites. The least equilibrated ordinary chondrites show evidence of aqueous alteration and have high D/H ratios possibly due to a deuterium-rich organic carrier. The aim of this study was to determine whether the CO3 chondrites, which have experienced similar secondary conditions to the type 3 ordinary chondrites, also contain a similar deuterium-rich carrier. To date a total of 5 CO3 meteorites, out of a set of 11 for which carbon and nitrogen isotopic data are available, have been analyzed. Ornans has not been analyzed yet, because it does not appear to fit in with the metamorphic sequence exhibited by the other CO3 chondrites; it also has an extremely high delta-D value of +2150 percent, unusual for such a comparatively equilibrated meteorite (type 3.4). Initial results indicate that the more equilibrated CO3's tend to have lower delta-D values, analogous to the higher petrologic type ordinary chondrites. However this is complicated by the effects of terrestrial weathering and the small data-set

The Beagle landing site in Isidis Planitia

The Mars probe Beagle 2 will land in Isidis Planitia. This region satisfies the engineering constraints and has evidence for particularly volatile-rich subsoil. Isidis provides a suitable place for the lander to search for H2O and organic matter

Identification of the Beagle 2 lander on Mars

The 2003 Beagle 2 Mars lander has been identified in Isidis Planitia at 90.43° E, 11.53° N, close to the predicted target of 90.50° E, 11.53° N. Beagle 2 was an exobiology lander designed to look for isotopic and compositional signs of life on Mars, as part of the European Space Agency Mars Express (MEX) mission. The 2004 recalculation of the original landing ellipse from a 3-sigma major axis from 174 km to 57 km, and the acquisition of Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment (HiRISE) imagery at 30 cm per pixel across the target region, led to the initial identification of the lander in 2014. Following this, more HiRISE images, giving a total of 15, including red and blue-green colours, were obtained over the area of interest and searched, which allowed sub-pixel imaging using super high-resolution techniques. The size (approx. 1.5 m), distinctive multilobed shape, high reflectivity relative to the local terrain, specular reflections, and location close to the centre of the planned landing ellipse led to the identification of the Beagle 2 lander. The shape of the imaged lander, although to some extent masked by the specular reflections in the various images, is consistent with deployment of the lander lid and then some or all solar panels. Failure to fully deploy the panels-which may have been caused by damage during landing-would have prohibited communication between the lander and MEX and commencement of science operations. This implies that the main part of the entry, descent and landing sequence, the ejection from MEX, atmospheric entry and parachute deployment, and landing worked as planned with perhaps only the final full panel deployment failing