Connection between the magnetic field strengths and the helium abundance in helium-rich stars     

Yu. V. Glagolevskii  F. G. Kopylova  L. S. Lyubimkov 《Astrophysics》1990,33(3):508-512

Special Astrophysical Observatory, USSR Academy of Sciences; Crimean Astrophysical Observatory, USSR Academy of Sciences. Translated from Astrofizika, Vol. 33, No. 3, pp. 363–370, November–December, 1990.  相似文献   

Oscillations of optical emission from flare stars and coronal loop diagnostics     

A. V. Stepanov  Yu. G. Kopylova  Yu. T. Tsap  E. G. Kupriyanova 《Astronomy Letters》2005,31(9):612-619

Based on an analogy between stellar and solar flares, we investigate the ten-second oscillations detected in the U and B bands on the star EV Lac. The emission pulsations are associated with fast magnetoacoustic oscillations in coronal loops. We have estimated the magnetic field, B ≈ 320 G; the temperature, T ≈ 3.7 × 10⁷ K; and the plasma density, n ≈ 1.6 × 10¹¹ cm^?3, in the region of energy release. We provide evidence suggesting that the optical emission source is localized at the loop footpoints.  相似文献   

The Ursa Major supercluster of galaxies: I. The luminosity function     

A. I. Kopylov  F. G. Kopylova 《Astronomy Letters》2001,27(3):140-149

Catalogs of bright galaxies in the central regions of 11 clusters in the Ursa Major supercluster are presented. Absolute and relative coordinates and total B and R magnitudes are given for each galaxy. Plates taken with the 2-m Tautenburg Observatory telescope and CCD images obtained with the 6-m and 1-m SAO telescopes are used. The luminosity functions (LFs) for galaxies in the cluster nuclei (3 Mpc×3 Mpc) and the composite LF for the supercluster are constructed. The composite LF is well fitted by a Schechter function with $M_B^ * = - 20\mathop .\limits^m 91$ , α=?1.02 and with $M_R^ * = - 22\mathop .\limits^m 39$ , α=?1.06. A comparison with the LFs of field galaxies and of various samples of clusters and superclusters shows that the Ursa Major supercluster have LF parameters characteristic of the field and, thus, differ from those of the Corona Borealis supercluster, which is apparently at a later stage of dynamical evolution.  相似文献   

Direct 40Ar/39Ar dating of Late Ordovician and Silurian brittle faulting in the southwestern Norwegian Caledonides          下载免费PDF全文

Thomas Scheiber  Giulio Viola  Camilla Maya Wilkinson  Morgan Ganerød  Øyvind Skår  Deta Gasser 《地学学报》2016,28(5):374-382

Structural data as well as U–Pb zircon and ⁴⁰Ar/³⁹Ar biotite and muscovite ages were collected from the Rolvsnes granodiorite in western Norway. The granodiorite intruded at c. 466 Ma, cooled quickly and escaped later viscous deformation. Brittle top‐to‐the‐NNW thrust faults (Set I) and WNW–ESE striking dextral strike‐slip faults (Set II) formed in a NNW–SSE transpressional regime. ⁴⁰Ar/³⁹Ar dating of synkinematic mica from both sets reveals a c. 450 Ma (Late Ordovician) age of faulting, which constrains early‐Caledonian brittle deformation. Set I and II faults are overprinted by a set of lower‐grade, variably oriented chlorite‐ and epidote‐coated faults (Set III) constraining WNW–ESE shortening. A lamprophyric dyke oriented compatibly with this stress field intruded at c. 435 Ma (Silurian), indicating that Set III formed at the onset of the Scandian Baltica–Laurentia collision. The preservation of Caledonian brittle structures indicates that the Rolvsnes granodiorite occupied a high tectonic level throughout the Caledonian orogeny.  相似文献   

Water chemical composition in the salt lakes of the Ubsunur depression (Southeastern Tuva)   总被引：1，自引：0，他引：1  

Ch. K. Oidup  R. Sh. Dongak  S. S. Shatskaya  Yu. G. Kopylova 《Geography and Natural Resources》2014,35(3):243-252

Presented are the results from determining the principal ion composition of the waters and the composition of chemical elements, including rare and rare-earth elements) in the waters of three salt lakes: Shara-Nur, Dus-Khol and Bai-Khol, on the territory of the drainless Ubsunur depression. Common to these lakes are their small depth, and their location in the bottoms of basins without outflow, between small bald mountains in the zone of dry climate with abrupt temperature fluctuations. More likely these lakes have their origins in the remnants of ancient water basins. Accumulation of salts in the lakes is associated with continental salinization processes.  相似文献   

Acoustic damping of fast kink oscillations of coronal loops     

Yu. T. Tsap  Yu. G. Kopylova 《Astronomy Letters》2001,27(11):737-744

The damping of fast kink oscillations of solar coronal loops attributable to the radiation of MHD waves into the surroundings is considered in the thin-tube approximation. The oscillation damping decrement is calculated both by using a new energy method and by solving the dispersion equation for magnetic-tube eigenmodes. The two approaches are in good agreement under appropriate assumptions. The damping is negligible if MHD waves are radiated perpendicular to the magnetic field. The low Q factor of the loop oscillations in active regions found with the TRACE space telescope is associated with the generation of running waves that propagate along magnetic field lines.  相似文献   

Time delay in pulsations of the nonthermal radiation of solar flares     

Yu. T. Tsap  T. B. Goldvarg  Yu. G. Kopylova  A. V. Stepanov 《Geomagnetism and Aeronomy》2013,53(7):827-830

The oscillations with a period of about 6 and 12 s in the nonthermal radiation of a solar flare occurred on November 5, 1992, are identified. The time-translated profiles of hard X-ray and microwave radiation flux are characterized by an anticorrelation. The specific features of the radiation fine time structure are interpreted using the model of the coronal magnetic mirror where fast magnetoacoustic modes are excited.  相似文献   

Structure of clusters with bimodal distribution of radial velocities of galaxies. IV: A1569     

A. I. Kopylov  F. G. Kopylova 《Astrophysical Bulletin》2012,67(1):17-28

We report the results of study of the A1569 cluster (12 ^h 36^m.3, +16°35′) and the neighboring A1589 cluster (12 ^h 41^m.3, +18°34′), making up a pair (a supercluster) with a projected size of about 10Mpc. This study is done within the framework of our program for investigating the galaxy clusters with bimodal velocity distributions (i.e., clusters where the velocities of subsystems differ by more than Δcz ∼ 3000 km/s). In the A1569 cluster we have identified two subsystems: A1569A (cz = 20613 km/s) and A1569B (cz = 23783 km/s). These subsystems have the line-of-sight velocity dispersions of 484 km/s and 493 km/s, and dynamic masses within the R ₂₀₀ radius equal to 1.8 × 10¹⁴ and 2.0 × 10¹⁴ M _⊙, respectively. We directly estimate the distances to these subsystems using three methods applied to earlytype galaxies: the Kormendy relation, photometric plane, and fundamental plane. To this end, we use the results of our observations made with the 1-m telescope of the SAO RAS and the data adopted from the SDSS DR7 catalog. We found that A1569 consists of two independent clusters. The A1569B cluster is located at the Hubble distance corresponding to its radial velocity. The A1569A cluster has a peculiar velocity of −1290 ± 630 km/s, which can be explained by the effect of the more massive A1589 cluster (with a mass of 7.9 × 10¹⁴ M _⊙) and of the supercluster where it resides. In all the four bimodal clusters that we studied within the framework of our program, A1035, A1775, A1831, and A1569, the subsystems are independent clusters lying close to the Hubble relation between redshift and distance.  相似文献   

Synchronization signals in the variations of groundwater chemical composition in Kamchatka in relation to the strong (M W ≥ 6.6) earthquakes     

G. N. Kopylova  L. N. Taranova 《Izvestiya Physics of the Solid Earth》2013,49(4):577-586

We consider the results of the statistical analysis using the methods of the principal components and canonical coherences applied to the processing of long (1986–2005) time series of hydrogeochemical observations at the flowing wells and springs in Kamchatka. The time-frequency diagrams of the evolution of informative statistics characterizing the collective behavior of multidimensional hydrogeochemical time series are constructed, and the time intervals and frequency bands where the synchronization signals (Lyubushin, 2007) appear are identified. The features of their occurrence are analyzed in comparison to the strong (M _w = 6.6?7.8) local earthquakes. It is found that such signals in the measurements of some multidimensional time series can arise both before and after earthquakes, i.e. these signals have a precursory (P2) and postseismic (P3) character.  相似文献   

Ambipolar diffusion and magnetic reconnection     

Yu. T. Tsap  A. V. Stepanov  Yu. G. Kopylova 《Astronomy Reports》2012,56(2):138-145

Some mechanisms for Joule dissipation of electric currents flowing in partially ionized hydrogen plasmas are analyzed in a three-fluid approximation. It is shown that ambipolar diffusion can be responsible for the annihilation of magnetic flux during collisions of ions with neutral atoms. The relative influences of the electron conductivity and the Cowling conductivity on the magnetic-field annihilation rate are examined in the frameworks of the Sweet-Parker reconnection model. The escape of plasma is an efficient mechanism for cooling current sheetswith thicknesses of hundreds of kilometers in the solar chromosphere. The origin of the solar chromospheric jets observed by the Hinode spacecraft is discussed.  相似文献