Loop Quantum Cosmology and Probability of Inflation

We study the measure on the set of initial conditions in remote past for Loop Quantum Cosmology with massive scalar field motivated by various choices of the measure present in the literature. The main finding of the paper is existence of an attractor at contracting phase of the universe, which, in addition to the well known attractor at expanding phase, predicts a very specific duration of inflationary stage with the number of e-foldings about 140.     

The two-body problem of a pseudo-rigid body and a rigid sphere

In this paper we consider the two-body problem of a spherical pseudo-rigid body and a rigid sphere. Due to the rotational and “re-labelling” symmetries, the system is shown to possess conservation of angular momentum and circulation. We follow a reduction procedure similar to that undertaken in the study of the two-body problem of a rigid body and a sphere so that the computed reduced non-canonical Hamiltonian takes a similar form. We then consider relative equilibria and show that the notions of locally central and planar equilibria coincide. Finally, we show that Riemann’s theorem on pseudo-rigid bodies has an extension to this system for planar relative equilibria.     

On some manifestations of Markov properties in long-term dynamics of thermal regime anomalies in Kazan

Long-term (1900–2004) dynamics of anomalies of annual mean air temperature, documented at the Meteorological Observatory of Kazan University, is considered as the behavior of a system passing through its certain states. By using the basic statements of random function theory, some features of the system behavior are studied from scientific and applied points of view.     

Rotation of the Hyades derived from Hipparcos data

Data from the Hipparcos catalog are used to study the internal kinematics of the Hyades cluster. Cluster members whose proper motions and parallaxes are known with precisions not less than 5 mas/yr and 3 mas were used. The proper motions were reduced to the cluster center. A correlation between a component of the tangential velocity and the parallax provides evidence for possible rotation of the cluster. The total velocity gradient is 0.04±0.03 km s^?1 pc^?1. The rotation axis is located perpendicular to the direction to the Hyades apex on the celestial sphere.     

The Pleiades apex and its kinematical structure

A study of cluster characteristics and internal kinematical structure of the middle-aged Pleiades open star cluster is presented. The individual star apexes and various cluster kinematical parameters including the velocity ellipsoid parameters are determined using both Hipparcos and Gaia data. Modern astrometric parameters were taken from the Gaia Data Release 1 (DR1) in combination with the Radial Velocity Experiment Fifth Data Release (DR5). The necessary set of parameters including parallaxes, proper motions and radial velocities are used for \(n=17\) stars from Gaia DR1+RAVE DR5 and for \(n=19\) stars from the Hipparcos catalog using SIMBAD data base. Single stars are used to improve accuracy by eliminating orbital movements. RAVE DR5 measurements were taken only for the stars with the radial velocity errors not exceeding \(2~\mbox{km}/\mbox{s}\). For the Pleiades stars taken from Gaia, we found mean heliocentric distance as \(136.8 \pm 6.4\) pc, and the apex position is calculated as: \(A_{CP}=92^{\circ }.52\pm 1^{\circ }.72\), \(D_{CP}=-42^{\circ }.28\pm 2^{\circ }.56\) by the convergent point method and \(A_{0}=95^{\circ }.59\pm 2^{\circ }.30\) and \(D_{0}=-50^{\circ }.90\pm 2^{\circ }.04\) using AD-diagram method (\(n=17\) in both cases). The results are compared with those obtained historically before the Gaia mission era.     

Kinematic Groups in the Corona of the Ursa Majoris Flow Indicated by Gaia Data

The internal kinematics of the Ursa Majoris stellar flow is considered. The details of the flow structure are considered, and new candidate members are searched for using high-precision Gaia DR1 TGAS data. The flow structure is studied using apex diagrams, which have been shown to be effective in studies of open clusters. To select member-stars of the flow, a chain of filters was applied to the spatial coordinates and velocities, photometric data, and elemental abundances of potential members. The nonuniform kinematic structure of the flow, manifest through its separation into different velocity directions for the core and three groups in the corona, is confirmed. Several filters were used to identify three candidate members. These included apex diagrams, M_V?(B?V)₀ diagrams, and the abundances of Fe, Mg, Al, Si, Ti, and Ni.     

Evolution of Comets

Astronomy Reports - Comets that were ejected by giant planets to the Oort cloud during the formation and evolution of planetary systems may get back to the orbits in the vicinity of the Sun with a...     

The Mineralogy of Iron and Manganese Ores of the Ushkatyn-III Deposit in Central Kazakhstan

Geology of Ore Deposits - The Ushkatyn-III in Central Kazakhstan is a weakly metamorphosed hydrothermal–sedimentary ore deposit of the Atasu type. For such objects, an assemblage of...     

Long-range forecasting of the dates of the stable 8°C crossing in average daily air temperature in the Volga Federal District

Physical principles are considered of asynchronous long-period relationships between the thermal state of the North Atlantic and the dates of the stable average daily air temperature crossing 8°C in spring and autumn in the Volga Federal District. The methodology and the results are discussed of testing the informativeness of the fields of sea surface temperature anomalies for long-range forecasting of the dates of the stable average daily air temperature crossing 8°C in the district.     

Mineralogical–Geochemical Features of Ice-Rafted Sediments in Some Arctic Regions

The quantitative mineral composition estimated using the Rietveld method and some geochemical features are considered for bulk samples of the ice-rafted sediments (IRS) from some Arctic regions. Layer silicates in the studied samples vary from ~20 to ~50%. They are dominated by micas and their decomposition products (illite and likely some part of smectites) at significant contents of kaolinite, chlorite, and transformation/decomposition products of the latter. A significant content of illite and muscovite among layer silicates in most IRS samples suggests that sources of the sedimentary material were mainly mineralogically similar to modern bottom sediments of the East Siberian and Chukchi seas, as well as presumably sediments of the eastern Laptev Sea. It is suggested that a significant kaolinite fraction in IRS samples from the North Pole area can be caused by the influx of ice-rafted fine-grained sedimentary material from the Beaufort or Chukchi seas, where kaolinite is supplied from the Bering Sea. Positions of IRS data points in the (La/Yb)_N–Eu/Eu*, (La/Yb)_N–(Eu/Sm)_N, and (La/Yb)_N–Th diagrams show that the studied samples contain variable proportions of erosion products of both mafic and felsic magmatic rocks and/or sufficiently mature sedimentary rocks. This conclusion is confirmed by localization of IRS data points in the Th/Co–La, Si/Al–Ce, and Si/Al–Sr diagrams.