Implementation of the Concept for Creating a Spacecraft Double-Launch System as a Part of the Upper Stages of the Fregat Family

Solar System Research - Abstract—Results of the implementation of a single concept for the development of the double launch system (SDZ) are presented, in particular the SDZ-La5 for the...     

Hyperspectral imaging of drill core from the Steen River impact structure,Canada: Implications for hydrothermal activity and formation of suevite‐like breccias

Hyperspectral imaging can be used to rapidly identify and map the spatial distributions of many minerals. Here, hyperspectral mapping in three wavelength regions (visible and near‐infrared, shortwave infrared, and thermal infrared) was applied to drill cores (ST001, ST002, and ST003) penetrating a continuous sequence of crater‐fill breccias from the Steen River impact structure in Alberta, Canada. The combined data sets reveal distinct mineralogical layering, with breccias derived predominantly from sedimentary rocks overlying those derived from granitic basement. This stratigraphy demonstrates that the breccias were not appreciably disturbed following deposition, which is inconsistent with formation models of similar breccias (suevites) by explosive impact melt–fluid interaction. At Steen River, volatiles from sedimentary target rocks were an inherent part of forming these enigmatic breccias. Approximately three quarters of terrestrial impact structures contain sedimentary target rocks; therefore, the role of volatiles in producing so‐called suevitic breccias may be more widespread than previously realized. The hyperspectral maps, specifically within the SWIR wavelength region, also delineate minerals associated with postimpact hydrothermal activity, including ammoniated clay and feldspar minerals not detectable using traditional techniques. These nitrogen‐bearing minerals may have originated from microbial processes, associated with oil‐ and gas‐producing units in the crater vicinity. Such minerals may have important implications for the production of habitable environments by impact‐induced hydrothermal activity on Earth and Mars.     

Hydrothermal activity on the CV parent body: New perspectives from the giant Transantarctic Mountains minimeteorite TAM5.29

TAM5.29 is an extraterrestrial dust grain, collected on the Transantarctic Mountains (TAM). Its mineralogy is dominated by an Fe‐rich matrix composed of platy fayalitic olivines and clasts of andradite surrounded by diopside‐jarosite mantles; chondrules are absent. TAM5.29 records a complex geological history with evidence of extensive thermal metamorphism in the presence of fluids at T < 300 °C. Alteration was terminated by an impact, resulting in shock melt veins and compaction‐orientated foliation of olivine. A second episode of alteration at lower temperatures (<100 °C) occurred postimpact and is either parent body or terrestrial in origin and resulted in the formation of iddingsite. The lack of chondrules is explained by random subsampling of the parent body, with TAM5.29 representing a matrix‐only fragment. On the basis of bulk chemical composition, mineralogy, and geological history TAM5.29 demonstrates affinities to the CV_ox group with a mineralogical assemblage in between the Allende‐like and Bali‐like subgroups (CV_oxA and TAM5.29 are rich in andradite, magnetite, and FeNiS, but CV_oxA lacks hydrated minerals, common in TAM5.29; conversely, CV_oxB are rich in hydrated phyllosilicates but contain almost pure fayalite, not found in TAM5.29). In addition, TAM5.29 has a slightly different metasomatic history, in between the oxidized and reduced CV metamorphic grades while also recording higher oxidizing conditions as compared to the known CV chondrites. This study represents the third CV‐like cosmic dust particle, containing a unique composition, mineralogy, and fabric, demonstrating variation in the thermal metamorphic history of the CV parent body(‐ies).     

Active Galactic Nuclei among Polar-Ring Galaxies

Astronomy Letters - Based on SDSS data, we consider the fraction of active galactic nuclei among polar-ring galaxies. We have found evidence for an excess of Seyfert galaxies and LINERS among...     

Surface and Fundamental Modes of Oscillations in Thin Coronal Loops

Astronomy Letters - The oscillations in thin magnetic flux tubes in the solar corona are considered. The surface and fundamental modes of oscillations are shown to be the main modes of fast and...     

On the Evolution of Bands in the Dynamic Spectra of Solar Type II Radio Bursts

Astronomy Letters - Based on an analysis of the dynamic spectra for solar flares in the meter wavelength range obtained with the ground-based Radio Solar Telescope Network, we consider the...     

The quasar population density as a result of the formation rate and the evolutionary pathes II. Adaption to the observation

The continuity equation of CAVALIERE et al. (1971) generalized to age-dependent luminosity evolution (BOLLER and LIEBSCHER 1989) is used to calculate quasar luminosity functions. For some combinations of source functions S(L, t) and evolutionary pathes M(L) we discuss the resulting N — m relations and the amount of the X-ray background and compare them with actual results of observation. We can exclude certain models, (S(L, t), M(L)). We cannot yet decide what the actual source function and the actual evolutionary path are.     

Essential properties of the cD galaxy in Abell 1795 — II. Radio structure

We consider current problems connected with the evolution of central dominant (cD) galaxies in clusters. In the second part of this series, internal properties of the cD galaxy — in particular its radio structure — are related to the appropriate ones of the cluster. The observations point to an earlier jet ejection along the major axis of the galaxy and a following change of the jet axis. From the existence of “hot-spot” like regions in different directions it is suggested that the radio engine would have to be intermittent with a relatively short period. Alternatively to the intermittent ejection scenario, the radio morphology of 4C 26.42 can be explained in the frame of the “standard” beam or jet model. The radio structure of 4C 26.42 being an inversion-symmetric configuration, which is probably due to galactic cannibalism, could be interpreted as a transition at the inner hot spots (at about 1 kpc) from supersonic, stable Fanaroff-Riley type II jets to subsonic, unstable FR I type structures (“plumes”). A quantitative investigation of the two scenarios for jet interaction with the surroudning interstellar/intercluster medium in 4C 26.42 gives parameter values in reasonable agreement with the ones discussed in the literature for related objects.