Statistical Study of Solar Radio Bursts at a Frequency of 210 MHz     

G. Salukvadze  N. Ograpishvili  D. Maghradze  D. Japaridze  T. Mdzinarishvili  B. Chargeishvili  T. Gachechiladze  Sh. Makandarashvili 《Astrophysics》2018,61(3):347-353

  相似文献   

Little rip cosmological models with quadratic equation of state with time dependent parameters     

R. D. Shelote  G. S. Khadekar 《Astrophysics and Space Science》2018,363(2):36

We have studied flat FRW cosmological model of the universe filled with an ideal fluid with quadratic equation of state (EOS) with time dependent parameters \(\omega(t)\) and \(\varLambda(t)\). We found the equation of the state parameter \(\omega(t)\) is less than ?1 and also found Little Rip (LR) and Pseudo Rip (PR) behavior for dark energy.  相似文献   

Age,Helium Content and Chemical Composition of Globular Clusters in the M31 Neighborhood and in our Galaxy     

M. E. Sharina  V. V. Shimansky  D. A. Khamidullina 《Astrophysical Bulletin》2018,73(3):318-334

We present the results of determinations of age, helium abundance (Y), metallicity ([Fe/H]), and estimations of abundances of the elements: C, N, O, Mg, Ca, Ti, Cr, Ni, Sr, and Ba of four globular clusters in the neighborhood of the Andromeda galaxy ([SD2009]GC7,Mayall II, Mackey-GC1 (MGC1), and Bol 298 (MGC6)) and of six Galactic clusters. Medium-resolution long-slit integrated-light spectra from the clusters under study were used to determine the parameters.Observations of extra-galactic objects were carried out with the 6-m SAO RAS telescope using the SCORPIO-1 multimode focal reducer. Galactic globular clusters NGC6341 (M92), NGC6838 (M71), and NGC7078 were observed with the CARELEC spectrograph at the 1.93-m telescope of the Haute-Provence Observatory. The integratedlight spectra of Galactic globular clusters NGC104, NGC6121 (M4), and NGC7078 (M15) were taken from the spectral library by Schiavon.We selected the best isochrone for each cluster by comparison of the shapes and intensities of the observed and theoretical Balmer line profiles.  相似文献   

About Superrotation in Venus     

D. J. Cirilo-Lombardo  M. Mayochi  F. O. Minotti  C. D. Vigh 《Solar System Research》2018,52(3):223-233

In this work we study in a general view slow rotating planets as Venus or Titan which present superrotating winds in their atmospheres. We are interested in understanding what mechanisms are candidates to be sources of net angular momentum to generate this kind of dynamics. In particular, in the case of Venus, in its atmosphere around an altitude of 100 km relative to the surface, there exists winds that perform a full rotation around the planet in four terrestrial days, whereas the venusian day is equivalent to 243 terrestrial ones. This phenomenon called superrotation is known since many decades. However, its origin and behaviour is not completely understood. In this article we analise and ponderate the importance of different effects to generate this dynamics.  相似文献   

A satellite relative motion model including $$J_2$$ and $$J_3$$J3 via Vinti’s intermediary     

Ashley D. Biria  Ryan P. Russell 《Celestial Mechanics and Dynamical Astronomy》2018,130(3):23

Vinti’s potential is revisited for analytical propagation of the main satellite problem, this time in the context of relative motion. A particular version of Vinti’s spheroidal method is chosen that is valid for arbitrary elliptical orbits, encapsulating \(J_2\), \(J_3\), and generally a partial \(J_4\) in an orbit propagation theory without recourse to perturbation methods. As a child of Vinti’s solution, the proposed relative motion model inherits these properties. Furthermore, the problem is solved in oblate spheroidal elements, leading to large regions of validity for the linearization approximation. After offering several enhancements to Vinti’s solution, including boosts in accuracy and removal of some singularities, the proposed model is derived and subsequently reformulated so that Vinti’s solution is piecewise differentiable. While the model is valid for the critical inclination and nonsingular in the element space, singularities remain in the linear transformation from Earth-centered inertial coordinates to spheroidal elements when the eccentricity is zero or for nearly equatorial orbits. The new state transition matrix is evaluated against numerical solutions including the \(J_2\) through \(J_5\) terms for a wide range of chief orbits and separation distances. The solution is also compared with side-by-side simulations of the original Gim–Alfriend state transition matrix, which considers the \(J_2\) perturbation. Code for computing the resulting state transition matrix and associated reference frame and coordinate transformations is provided online as supplementary material.  相似文献   

A Regression Model of Microwave Emission of a Water Surface at 37.5 GHz     

Sazonov  D. S. 《Izvestiya Atmospheric and Oceanic Physics》2018,54(9):1249-1256

Izvestiya, Atmospheric and Oceanic Physics - This paper presents the functional dependence of the microwave emission of a rough water surface at a frequency of 37.5 GHz (wavelength of ~8 mm). The...  相似文献   

Baikal Electromagnetic Experiment     

Korotaev  S. M.  Budnev  N. M.  Serdyuk  V. O.  Orekhova  D. A.  Kruglyakov  M. S.  Kiktenko  E. O.  Mirgazov  R. R.  Zurbanov  V. L.  Gorokhov  Ju. V.  Ryabov  E. V. 《Izvestiya Atmospheric and Oceanic Physics》2018,54(11):1569-1594

Izvestiya, Atmospheric and Oceanic Physics - The vertical component of the electric field Ez in the hydrosphere is not contaminated by the telluric component and therefore can effectively be used...  相似文献   

Low resolution spectroscopy of selected Algol systems     

Shanti Priya Devarapalli  Rukmini Jagirdar  M. Parthasarathy  D. K. Sahu  Vijay Mohan  B. C. Bhatt  Vineet S. Thomas 《Astrophysics and Space Science》2018,363(4):69

The analysis of spectroscopic data for 30 Algol-type binaries is presented. All these systems are short period Algols having primaries with spectral types B and A. Dominant spectral lines were identified for the spectra collected and their equivalent widths were calculated. All the spectra were examined to understand presence of mass transfer, a disk or circumstellar matter and chromospheric emission. We also present first spectroscopic and period study for few Algols and conclude that high resolution spectra within and outside the primary minimum are needed for better understanding of these Algol type close binaries.  相似文献   

Understanding the Role of Mass-Unloading in a Filament Eruption     

J. M. Jenkins  D. M. Long  L. van Driel-Gesztelyi  J. Carlyle 《Solar physics》2018,293(1):7

We describe a partial filament eruption on 11 December 2011 that demonstrates that the inclusion of mass is an important next step for understanding solar eruptions. Observations from the Solar Terrestrial Relations Observatory-Behind (STEREO-B) and the Solar Dynamics Observatory (SDO) spacecraft were used to remove line-of-sight projection effects in filament motion and correlate the effect of plasma dynamics with the evolution of the filament height. Flux cancellation and nearby flux emergence are shown to have played a role in increasing the height of the filament prior to eruption. The two viewpoints allow the quantitative estimation of a large mass-unloading, the subsequent radial expansion, and the eruption of the filament to be investigated. A 1.8 to 4.1 lower-limit ratio between gravitational and magnetic-tension forces was found. We therefore conclude that following the loss-of-equilibrium of the flux-rope, the radial expansion of the flux-rope was restrained by the filamentary material until 70% of the mass had evacuated the structure through mass-unloading.  相似文献   

Holocene relative sea level history and Storegga tsunami run‐up in Lyngen,northern Norway          下载免费PDF全文

Henrik Rasmussen  Stein Bondevik  Geoffrey D. Corner 《第四纪科学杂志》2018,33(4):393-408

  相似文献