Energetic electron signatures of Saturn's smaller moons: Evidence of an arc of material at Methone

We present several energetic charged particle microsignatures of two Lagrange moons, Telesto and Helene, measured by the MIMI/LEMMS instrument. These small moons absorb charged particles but their effects are usually obscured by Tethys and Dione, the two larger saturnian satellites that occupy the same orbits. The scales and structures of these microsignatures are consistent with standard models for electron absorption from asteroid-sized moons in Saturn's radiation belts. In the context of these observations, we also examine the possibility that the 3 km Satellite Methone is responsible for two electron microsignatures detected by Cassini close to this moon's orbit. We infer that a previously undetected arc of material exists at Methone's orbit (R/2006 S5), we speculate how such a structure could form and what its physical characteristics and location could be. The origin of this arc could be linked to a possible presence of a faint ring produced by micrometeoroid impacts on Methone's surface, to E-ring dust clump formation at that distance or to temporary dust clouds produced by enceladian activity that spiral inwards under the effect of non-gravitational forces.     

Molecular line mapping of the giant molecular cloud associated with RCW 106 – II. Column density and dynamical state of the clumps

We present a fully sampled C¹⁸O (1–0) map towards the southern giant molecular cloud (GMC) associated with the H  ii region RCW 106, and use it in combination with previous ¹³CO (1–0) mapping to estimate the gas column density as a function of position and velocity. We find localized regions of significant ¹³CO optical depth in the northern part of the cloud, with several of the high-opacity clouds in this region likely associated with a limb-brightened shell around the H  ii region G333.6−0.2. Optical depth corrections broaden the distribution of column densities in the cloud, yielding a lognormal distribution as predicted by simulations of turbulence. Decomposing the ¹³CO and C¹⁸O data cubes into clumps, we find relatively weak correlations between size and linewidth, and a more sensitive dependence of luminosity on size than would be predicted by a constant average column density. The clump mass spectrum has a slope near −1.7, consistent with previous studies. The most massive clumps appear to have gravitational binding energies well in excess of virial equilibrium; we discuss possible explanations, which include magnetic support and neglect of time-varying surface terms in the virial theorem. Unlike molecular clouds as a whole, the clumps within the RCW 106 GMC, while elongated, appear to show random orientations with respect to the Galactic plane.     

The Canadian Meteor Orbit Radar Meteor Stream Catalogue

The Canadian Meteor Orbit Radar is a multi-frequency backscatter radar which has been in routine operation since 1999, with an orbit measurement capability since 2002. In total, CMOR has measured over 2 million orbits of meteoroids with masses greater than 10 μg, while recording more than 18 million meteor echoes in total. We have applied a two stage comparative technique for identifying meteor streams in this dataset by making use of clustering in radiants and velocities without employing orbital element comparisons directly. From the large dataset of single station echoes, combined radiant activity maps have been constructed by binning and then stacking each years data per degree of solar longitude. Using the single-station mapping technique described in Jones and Jones (Mon Not R Astron Soc 367:1050–1056, 2006) we have identified probable streams from these single station observations. Additionally, using individual radiant and velocity data from the multi-station velocity determination routines, we have utilized a wavelet search algorithm in radiant and velocity space to construct a list of probable streams. These two lists were then compared and only streams detected by both techniques, on multiple frequencies and in multiple years were assigned stream status. From this analysis we have identified 45 annual minor and major streams with high reliability.     

Deformation and mineralisation in the Scotty Creek Basin,Agnew district,Eastern Goldfields,Western Australia: evidence for D1- and D3-related gold mineralisation

Gold deposits in the Agnew district display markedly different structural styles. The Waroonga and Songvang deposits are hosted in layer-parallel extensional shears formed under highly ductile conditions. In contrast, the New Holland–Genesis deposits are shallow-dipping quartz-filled brittle fractures and breccia zones that cut across the tightly folded bedding and formed during east–west compression. It is difficult to attribute their formation to a single compressive event. The Waroonga and Songvang deposits formed during D₁ extension, uplift and exhumation of the Agnew granitic complex and formation of the Scotty Creek Basin at ca 2670–2660?Ma. The New Holland–Genesis deposits formed during east–west D₃ compression at about ca 2650–2630?Ma. An S₁ foliation wraps around the Agnew granitic complex and L₁ stretching lineations form a radial pattern around the granite, consistent with formation during D₁ uplift of the composite granite body. Uplift and erosion of granite bodies in the surrounding area provide a source for the granite clasts in the upper parts of the Scotty Creek Basin. As clasts in the basin are undeformed, no significant deformation occurred prior to the uplift and erosion of the source granites in this area. Syn-tectonic emplacement of the Lawlers Tonalite during formation of the Scotty Creek Basin at ca 2665?Ma may have provided a good heat/fluid source for the mineralising systems during the first gold event. The distribution of the large deposits along the western edge of the Agnew granitic complex indicates that the extensional shear along the granite contact is a first-order control on gold deposition by providing a conduit for rising hydrothermal fluids. The northerly trend of high-grade shoots in the Waroonga deposit coincides with early north-trending growth faults, which are also likely fluid conduits.     

Indigenous Land Management in Peri-Urban Landscapes: An Australian Example

This article examines roles, opportunities, and challenges for Indigenous land management in rapidly developing landscapes through a case study of Bunya Bunya Country Aboriginal Corporation, a not-for-profit organization on the Sunshine Coast, Queensland, Australia. An analysis of data collected through semistructured interviews, participant observation, and analysis of secondary sources reveals that Aboriginal land managers work in a variety of roles to manage issues affecting the local environment and cultural heritage sites. These efforts are challenged by the absence of Native Title and colonial land management policies, which restrict Aboriginal involvement in land management. We conclude that there is a need for alternative pathways to engage with Aboriginal land managers who cannot, or choose not to, proceed with Native Title. Decolonized decision-making tools and sustainable enterprises are viable opportunities that partially address these challenges and could deliver tangible socio-economic and cultural benefits to local Aboriginal and non-Aboriginal people.     

Does Magnetic Flux Submerge at Flux Cancelation Sites?

Simultaneous measurements of the magnetic fields in the photosphere and chromosphere were used to investigate if magnetic flux is submerging at sites between adjacent opposite polarity magnetic network elements in which the flux is observed to decrease or `cancel'. These data were compared with chromospheric and coronal intensity images to establish the timing of the emission structures associated with these magnetic structures as a function of height. We found that most of the cancelation sites show either that the bipole is observed longer in the photosphere than in the chromosphere and corona (44%) or that the timing difference of the disappearance of the bipole between these levels of the atmosphere is unresolved. The magnetic axis lengths of the structures associated with the cancelation sites are on average slightly smaller in the chromosphere than the photosphere. These observations suggest that magnetic flux is retracting below the surface for most, if not all, of the cancelation sites studied.