Disentangling of the Spectra of Binary Stars – Principles, Results and Future Development

The method of spectra disentangling is reviewed in context with related techniques. New generalizations (disentangling with constraints) and applications (for spectroastrometry) are also described.     

Constraining genesis and geotectonic setting of metavolcanic complexes: a multidisciplinary study of the Devonian Vrbno Group (Hrubý Jeseník Mts., Czech Republic)

The low-grade metavolcanic/volcanosedimentary complex of the Devonian Vrbno Group (Silesicum, NE Bohemian Massif, Czech Republic) occurs in two ~NE–SW trending belts, separated by tectonic slices of Cadomian metagranitic paraautochton. (1) The basic–intermediate lavas of the calc-alkaline Western Volcanic Belt came from a moderately depleted mantle $ \left( {\varepsilon_{\text{Nd}}^{370} \sim + 3} \right) $ . Rare rhyolites (374.0 ± 1.7 Ma: 2σ, LA–ICP–MS U–Pb Zrn) were derived most likely from immature crust or by extensive fractionation of primary basaltic melts. The rock association is interpreted as a vestige of a deeply dissected continental arc. (2) The Eastern Volcanic Belt consists mainly of (nearly) contemporaneous (371.0 ± 1.4 Ma) felsic alkaline lavas with high HFSE contents, as well as high Ga/Al and Fe/Mg ratios, typical of within-plate igneous setting. The petrology and Nd–Sr isotopic data point to a high-T anatexis of a young metagranitic crust, resembling the Cadomian (Brunovistulian) basement, in a back-arc setting. The attenuated Brunovistulian lithosphere could have partially melted by the heat provided by the upwelling asthenosphere and/or underplating basic magma. (3) Finally, the region was penetrated by numerous subalkaline, MORB/EMORB-like dolerite sheets—a hallmark of the considerable crustal thinning.     

A combined statistical approach for evaluation of the effects of land use,agricultural and urban activities on stream water chemistry in small tile-drained catchments of south Bohemia,Czech Republic

This work evaluates the changes of nitrate-nitrogen (NO₃-N), ammonium-nitrogen (NH₄-N), total phosphorus (P) and chemical oxygen demand (COD) concentrations in stream waters as related to the land use/land cover (LULC) alterations within eight small (5–39 km²) tile-drained catchments in the southern part of The Czech Republic in the period 1993–2010, when massive grassing of arable land took place. The robust tools of seasonal Mann–Kendall trend test and LOcally WEighted Scatterplot Smoothing methods were employed to reveal trends of the monitored parameters with adjustment to hydrology. Using principal component analysis and multiple regressions, statistically significant factors with highest impacts on the assessed water quality parameters were identified. Besides indicators of LULC changes in the catchments and their various zones, information of built tile drainage systems were used along with factors reflecting point pollution sources such as the population number, sewerage type and proximity to a watercourse, effectiveness of wastewater treatment, and number of livestock units. The change in LULC was essential only for NO₃-N concentrations, when grassing of arable land, presence of water ponds, areas of permanent cultures and also areas of drained land explained up to 90.6 % NO₃-N variability and nitrate-nitrogen concentrations showed a significantly decreasing trend in all monitored catchments during the evaluated period. LULC changes within infiltration vulnerable zones were discovered as less important for the assessed water quality parameters compared to LULC changes in the whole catchment area. However, for NH₄-N, P and COD, the results did not enable a definite quantification of the effects of LULC changes. The influence of non-point pollution sources on these parameters was revealed as uncertain and was heavily overshadowed by point sources, in particular by wastewater management, and livestock numbers, although the proportion of arable land in tile drainage subcatchments was discovered fundamental in case of the COD. The increasing numbers of livestock, population, and changes in sewage treatment led in some catchments to significant worsening of water quality. Achieved findings may be critical for supporting water quality policy and management decisions.     

Radar and optical observations and physical modeling of triple near-Earth Asteroid (136617) 1994 CC

We report radar, photometric, and spectroscopic observations of near-Earth Asteroid (136617) 1994 CC. The radar measurements were obtained at Goldstone (8560 MHz, 3.5 cm) and Arecibo (2380 MHz, 12.6 cm) on 9 days following the asteroid’s approach within 0.0168 AU on June 10, 2009. 1994 CC was also observed with the Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes (PROMPT) on May 21 and June 1-3. Visible-wavelength spectroscopy was obtained with the 5-m Hale telescope at Palomar on August 25. Delay-Doppler radar images reveal that 1994 CC is a triple system; along with (153591) 2001 SN263, this is only the second confirmed triple in the near-Earth population. Photometry obtained with PROMPT yields a rotation period for the primary P = 2.38860 ± 0.00009 h and a lightcurve amplitude of ∼0.1 mag suggesting a shape with low elongation. Hale telescope spectroscopy indicates that 1994 CC is an Sq-class object. Delay-Doppler radar images and shape modeling reveal that the primary has an effective diameter of 0.62 ± 0.06 km, low pole-on elongation, few obvious surface features, and a prominent equatorial ridge and sloped hemispheres that closely resemble those seen on the primary of binary near-Earth Asteroid (66391) 1999 KW4. Detailed orbit fitting reported separately by Fang et al. (Fang, J., Margot, J.-L., Brozovic, M., Nolan, M.C., Benner, L.A.M., Taylor, P.A. [2011]. Astron. J. 141, 154-168) gives a mass of the primary of 2.6 × 10¹¹ kg that, coupled with the effective diameter, yields a bulk density of 2.1 ± 0.6 g cm⁻³. The images constrain the diameters of the inner and outer satellites to be 113 ± 30 m and 80 ± 30 m, respectively. The inner satellite has a semimajor axis of ∼1.7 km (∼5.5 primary radii), an orbital period of ∼30 h, and its Doppler dispersion suggests relatively slow rotation, 26 ± 12 h, consistent with spin-orbit lock. The outer satellite has an orbital period of ∼9 days and a rotation period of 14 ± 7 h, establishing that the rotation is not spin-orbit locked. Among all binary and triple systems observed by radar, at least 25% (7/28) have a satellite that rotates more rapidly than its orbital period. This suggests that asynchronous configurations with P_rotation < P_orbital are relatively common among multiple systems in the near-Earth population. 1994 CC’s outer satellite has an observed maximum separation from the primary of ∼5.7 km (∼18.4 primary radii) that is the largest separation relative to primary radius seen to date among all 36 known binary and triple NEA systems. 1994 CC, (153591) 2001 SN263, and 1998 ST27 are the only triple and binary systems known with satellite separations >10 primary radii, suggesting either a detection bias, or that such widely-separated satellites are relatively uncommon in NEA multiple systems.     

Electron transport and precipitation at Mercury during the MESSENGER flybys: Implications for electron-stimulated desorption

To examine electron transport, energization, and precipitation in Mercury's magnetosphere, a hybrid simulation study has been carried out that follows electron trajectories within the global magnetospheric electric and magnetic field configuration of Mercury. We report analysis for two solar-wind parameter conditions corresponding to the first two MESSENGER Mercury flybys on January 14, 2008, and October 6, 2008, which occurred for similar solar wind speed and density but contrasting interplanetary magnetic field (IMF) directions. During the first flyby the IMF had a northward component, while during the second flyby the IMF was southward. Electron trajectories are traced in the fields of global hybrid simulations for the two flybys. Some solar wind electrons follow complex trajectories at or near where dayside reconnection occurs and enter the magnetosphere at these locations. The entry locations depend on the IMF orientation (north or south). As the electrons move through the entry regions they can be energized as they execute non-adiabatic (demagnetized) motion. Some electrons become magnetically trapped and drift around the planet with energies on the order of 1–10 keV. The highest energy of electrons anywhere in the magnetosphere is about 25 keV, consistent with the absence of high-energy (>35 keV) electrons observed during either MESSENGER flyby. Once within the magnetosphere, a fraction of the electrons precipitates at the planetary surface with fluxes on the order of 10⁹ cm⁻² s⁻¹ and with energies of hundreds of eV. This finding has important implications for the viability of electron-stimulated desorption (ESD) as a mechanism for contributing to the formation of the exosphere and heavy ion cloud around Mercury. From laboratory estimates of ESD ion yields, a calculated ion production rate due to ESD at Mercury is found to be on par with ion sputtering yields.     

Öpik-type collision probability for high-inclination orbits

The classical Öpik theory provides an estimate of the collision probability between two bodies on bound, heliocentric or planetocentric orbits under restrictive assumptions of: (i) constant eccentricity and inclination, and (ii) uniform circulation of the longitude of node and argument of pericenter. These assumptions are violated whenever either of the orbits has a large inclination with respect to the local Laplace plane or large eccentricity, and their motion is perturbed by an exterior (tidal) gravitational field of a planet or the Sun. In this situation, known as the Lidov–Kozai regime, the eccentricity and inclination values exhibit large and correlated oscillations. At the same time, the longitude of node and the argument of pericenter may have strongly nonlinear time evolution, with the latter being even bound to a small interval of values. Here we develop a new Öpik-type collision probability theory which is valid even for highly inclined and/or eccentric orbits of the projectile. We assume that the orbit of the target is circular and in the local Laplace plane. Such a generalized setting is necessary, as an example, to correctly estimate the terrestrial impact fluxes of sporadic micrometeoroids on high-inclination orbits (notably those from the toroidal source and the associated helion and anti-helion arcs).     

The detection of common cycles in magnetic susceptibility observed in distant magnetostratigraphic sections

The data obtained by former magnetostartigraphic studies of sections of Jurassic/Cretaceous age located at Brodno, W. Slovakia, and Puert Esca?o, S. Spain, about 2200 km apart, are herein reprocessed in order to detect environmental cycles recorded by magnetic susceptibility. The dating of the samples with respect to the geomagnetic polarity time scale enabled to estimate the power spectrum up to the frequency of 11 Myr^?1 as well as the phases corresponding to the spectral maxima. Using these frequencies and phases, we linked together the cycles detected with different sections. The hypothesis that their similarity results only from random coincidence had to be rejected for seven pairs of these cycles. The frequencies of these cycles are related to those of the recent modes of orbital eccentricity.