The Paleoproterozoic Kolvitsa Anorthosite Massif: New Data on the U–Pb Age (ID TIMS) and Geochemical Features of Zircon     

Steshenko  E. N.  Nikolaev  A. I.  Bayanova  T. B.  Drogobuzhskaya  S. V.  Chashchin  V. V.  Serov  P. A.  Lyalina  L. M.  Novikov  A. I.  Elizarov  D. V. 《Doklady Earth Sciences》2018,479(1):366-370

Doklady Earth Sciences - The rocks and minerals of the Kolvitsa massif are studied by complex isotopic–geochronological and geochemical (U–Pb, Sm–Nd, REE contents of zircons)...  相似文献   

Mineral Composition and Structure of the Sverdlovsk Meteorite (H4-5)     

Berzin  S. V.  Koroteev  V. A.  Ivanov  K. S.  Kleimenov  D. A.  Kiseleva  D. V.  Cherednichenko  N. V. 《Doklady Earth Sciences》2018,479(1):390-392

A fragment of the Sverdlovsk Meteorite, which was found in 1985 in the Central Urals, is studied by modern analytical methods. It belongs to H chondrites of petrologic type 4–5; shock stage of meteorite is S1-2, terrestrial weathering is W1. The composition of minerals of the meteorite is studied. It is found for the first time that the metal and sulfides are concentrated in fine veinlets of the recrystallized matrix of the chondrite and are accompanied by segregations of metal and troilite inside these veinlets. The distribution of trace elements of the metal phase of the meteorite is studied.

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Recognition of Strong Earthquake Prone Areas in the Altai–Sayan–Baikal Region     

Gorshkov  A. I.  Soloviev  A. A.  Zharkikh  Ju. I. 《Doklady Earth Sciences》2018,479(1):412-414

The locations of areas prone to strong earthquakes (M ≥ 6.0) in the Altai–Sayan–Baikal region are determined. Based on a scheme of morphostructural zoning of the region and by using the CORA-3 pattern recognition algorithm, all intersections of morphostructural lineaments are separated into two classes: the highly seismic intersections in the vicinities of which strong earthquakes can occur and low seismic in the vicinities of which only earthquakes with M < 6.0 are possible. Recognition was performed for the vectors the components of which were measured values of the geological–geophysical characteristics describing the respective intersection. The result obtained allows the zones of high seismic hazard to be identified more reliably in the region.

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Geochemical Features of Cupriferous Sandstones in the Orenburg Area of the Ural Region     

Volkov  A. V.  Novikov  I. A.  Razumovskiy  A. A.  Murashov  K. Yu.  Sidorova  N. V.  Sidorov  A. A. 《Doklady Earth Sciences》2018,479(1):393-396

The new geochemical data obtained of cupriferous sandstones of the Orenburg area of the Ural region show that the Permian host stratum could have served as the source of rare-earth elements and other microelements for the ore-forming fluids. They confirm the possibility of using a convection model to explain the genesis of the copper ores studied. This model indicates the likely multistage development of mineralization to significant depths, like in the Manto deposits in Chili. Consequently, the Permian cupriferous sandstones of the southwestern area of the Ural region can be considered a very promising source of raw material for the development of copper industry in the area.

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Flares of the H<Subscript>2</Subscript>O Maser Emission in the Young Stellar Object GH<Subscript>2</Subscript>O 092.67+03.07 (IRAS 21078+5211)     

V. V. Krasnov  E. E. Lekht  V. M. Minnebaev  M. I. Pashchenko  G. M. Rudnitskii  A. M. Tolmachev 《Astronomy Reports》2018,62(3):200-212

The results of monitoring the H₂O maser observed toward the region GH₂O 092.67+03.07 (IRAS 21078+5211) located in the Giant Molecular Cloud Cygnus OB7 are presented. The observations were carried out with the 22-m radio telescope of the Pushchino Radio Astronomy Observatory in 2006–2017. Strong flares of the H₂O maser emission with flux densities up to 19 800 Jy were detected. The flares exhibited both global (over the source) and local characters. All the flares were accompanied by strong variations in the H₂O spectra within the corresponding radial-velocity ranges. Individual H₂O components form both compact clusters and chains 1–2-AU long. Analysis of the variations of the fluxes, radial velocities, and line shapes of features during the flares showed that the medium may be strongly fragmented, with small-scale turbulent motions taking place in the H₂Omaser region.  相似文献   

Spots and the Activity of Stars in the Hyades Cluster from Observations with the Kepler Space Telescope (K2)     

I. S. Savanov  E. S. Dmitrienko 《Astronomy Reports》2018,62(3):238-242

Observations of the K2 mission (continuing the program of the Kepler Space Telescope) are used to estimate the spot coverage S (the fractional area of spots on the surface of an active star) for stars of the Hyades cluster. The analysis is based on data on the photometric variations of 47 confirmed single cluster members, together with their atmospheric parameters, masses, and rotation periods. The resulting values of S for these Hyades objects are lower than those stars of the Pleiades cluster (on average, by ΔS ~ 0.05?0.06). A comparison of the results of studies of cool, low-mass dwarfs in the Hyades and Pleiades clusters, as well as the results of a study of 1570 M stars from the main field observed in the Kepler SpaceMission, indicates that the Hyades stars are more evolved than the Pleiades stars, and demonstrate lower activity. The activity of seven solar-type Hyades stars (S = 0.013 ± 0.006) almost approaches the activity level of the present-day Sun, and is lower than the activity of solar-mass stars in the Pleiades (S = 0.031 ± 0.003). Solar-type stars in the Hyades rotate faster than the Sun (〈P〉 = 8.6 ^d ), but slower than similar Pleiades stars.  相似文献   

The Spots and Activity of Stars in the Beehive Cluster Observed by the Kepler Space Telescope (K2)     

I. S. Savanov  E. S. Kalinicheva  E. S. Dmitrienko 《Astronomy Reports》2018,62(5):352-358

The spottedness parameters S (the fraction of the visible surface of the star occupied by spots) characterizing the activity of 674 stars in the Beehive Cluster (age 650 Myr) are estimated, together with variations of this parameter as a function of the rotation period, Rossby number Ro and other characteristics of the stars. The activity of the stars in this cluster is lower than the activity of stars in the younger Pleiades (125 Myr). The average S value for the Beehive Cluster stars is 0.014, while Pleiades stars have the much higher average value 0.052. The activity parameters of 61 solar-type stars in the Beehive Cluster, similar Hyades stars (of about the same age), and stars in the younger Pleiades are compared. The average S value of such objects in the Beehive Cluster is 0.014± 0.008, nearly coincident with the estimate obtained for solar-type Hyades stars. The rotation periods of these objects are 9.1 ± 3.4 day, on average, in agreement with the average rotation period of the Hyades stars (8.6 ^d ). Stars with periods exceeding 3–4 ^d are more numerous in the Beehive Cluster than in the Pleiades, and their periods have a larger range, 3–30 ^d . The characteristic dependence with a kink at Ro (saturation) = 0.13 is not observed in the S–Rossby number diagram for the Beehive and Hyades stars, only a clump of objects with Rossby numbers Ro > 0.7. The spottedness data for the Beehive Cluster and Hyades stars are in good agreement with the S values for dwarfs with ages of 600–700 Myr. This provides evidence for the reliability of the results of gyrochronological calibrations. The data for the Beehive and Pleiades stars are used to analyze variations in the spot-forming activity for a large number of stars of the same age that are members of a single cluster. A joint consideration of the data for two clusters can be used to draw conclusions about the time evolution of the activity of stars of different masses (over a time interval of the order of 500 Myr).  相似文献   

A Pulsar Time Scale Based on Parkes Observations in 1995–2010     

A. E. Rodin  V. A. Fedorova 《Astronomy Reports》2018,62(6):378-382

Timing of highly stable millisecond pulsars provides the possibility of independently verifying terrestrial time scales on intervals longer than a year. An ensemble pulsar time scale is constructed based on pulsar timing data obtained on the 64-m Parkes telescope (Australia) in 1995–2010. Optimal Wiener filters were applied to enhance the accuracy of the ensemble time scale. The run of the time-scale difference PT_ens?TT(BIPM2011) does not exceed 0.8 ± 0.4 μs over the entire studied time interval. The fractional instability of the difference PT_ens?TT(BIPM2011) over 15 years is σ _z = (0.6 ± 1.6) × 10^?15, which corresponds to an upper limit for the energy density of the gravitational-wave background Ω _g h² ~ 10^?10 and variations in the gravitational potential ~10^?15 Hz at the frequency 2 × 10^?9 Hz.  相似文献   

Observations of Near-Earth Optical Transients with the Lomonosov Space Observatory     

V. M. Lipunov  E. S. Gorbovskoy  V. G. Kornilov  V. V. Chazov  M. I. Panasyuk  S. I. Svertilov  I. V. Yashin  V. L. Petrov  V. V. Kallegaev  A. A. Amelushkin  D. M. Vlasenko 《Astronomy Reports》2018,62(7):426-435

The results of observations with the MASTER-SHOK robotic wide-field optical cameras onboard the Lomonosov Space Observatory carried out in 2016 are presented. In all, the automated transient detection system transmitted 22 181 images of moving objects with signal-to-noise ratios greater than 5 to the Earth. Approximately 84% of these images are identified with well-known artificial Earth satellites (including repeated images of the same satellite) and fragments of such satellites (space debris), according to databases of known satellites. The remaining 16% of the images are relate to uncatalogued objects. This first experience in optical space-based monitoring of near-Earth space demonstrates the high efficiency and great potential of using large-aperture cameras in space, based on the software and technology of the MASTER robotic optical complexes (the Mobile Astronomical System of TElescope- Robots (MASTER) global network of robotic telescopes of Lomonosov Moscow State University).  相似文献   

Relativistic Metrology of Near-Earth Space–Time and Its Practical Applications     

Fateev  V. F. 《Astronomy Reports》2018,62(12):1036-1041

Astronomy Reports - Results of studies of relativistic effects for the time and frequency shifts for an Earth–satellite system of atomic clocks, and also for moving clocks on the Earth, are...  相似文献