Discovery of the First Interstellar Comet and the Spatial Density of Interstellar Objects in the Solar Neighborhood     

Borisov  G. V.  Shustov  B. M. 《Solar System Research》2021,55(2):124-131

Solar System Research - The discovery of the first interstellar comet 2I/Borisov confirmed the astronomers’ speculation that the passage through the solar system of relatively large objects...  相似文献   

Reduction and relative equilibria for the two-body problem on spaces of constant curvature     

A. V. Borisov  L. C. García-Naranjo  I. S. Mamaev  J. Montaldi 《Celestial Mechanics and Dynamical Astronomy》2018,130(6):43

We consider the two-body problem on surfaces of constant nonzero curvature and classify the relative equilibria and their stability. On the hyperbolic plane, for each \(q>0\) we show there are two relative equilibria where the masses are separated by a distance q. One of these is geometrically of elliptic type and the other of hyperbolic type. The hyperbolic ones are always unstable, while the elliptic ones are stable when sufficiently close, but unstable when far apart. On the sphere of positive curvature, if the masses are different, there is a unique relative equilibrium (RE) for every angular separation except \(\pi /2\). When the angle is acute, the RE is elliptic, and when it is obtuse the RE can be either elliptic or linearly unstable. We show using a KAM argument that the acute ones are almost always nonlinearly stable. If the masses are equal, there are two families of relative equilibria: one where the masses are at equal angles with the axis of rotation (‘isosceles RE’) and the other when the two masses subtend a right angle at the centre of the sphere. The isosceles RE are elliptic if the angle subtended by the particles is acute and is unstable if it is obtuse. At \(\pi /2\), the two families meet and a pitchfork bifurcation takes place. Right-angled RE are elliptic away from the bifurcation point. In each of the two geometric settings, we use a global reduction to eliminate the group of symmetries and analyse the resulting reduced equations which live on a five-dimensional phase space and possess one Casimir function.  相似文献   

Study of Lateral Sedimentation in the Western Atlantic on Cruise 53 of the R/V Akademik Ioffe     

Ivanova  E. V.  Murdmaa  I. O.  Borisov  D. G.  Ovsepyan  E. A.  Simagin  N. V.  Mutovkin  A. D.  Nemchenko  N. V.  Kornilova  M. O.  Sud’in  V. V.  Novikov  Yu. V. 《Oceanology》2018,58(6):932-934

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Spectroscopic Redshift Determination for a Sample of Distant Quasars Detected by the SRG Observatory Based on RTT-150 Observations. II     

Bikmaev  I. F.  Irtuganov  E. N.  Nikolaeva  E. A.  Sakhibullin  N. A.  Gumerov  R. I.  Sklyanov  A. S.  Glushkov  M. V.  Khamitov  I. M.  Borisov  V. D.  Burenin  R. A.  Zaznobin  I. A.  Krivonos  R. A.  Lyapin  A. R.  Medvedev  P. S.  Meshcheryakov  A. V.  Sazonov  S. Yu.  Sunyaev  R. A.  Khorunzhev  G. A.  Gilfanov  M. R. 《Astronomy Letters》2021,47(5):277-290

Astronomy Letters - Results of the spectroscopic observations at the 1.5-m Russian–Turkish telescope for another group of 12 X-ray sources discovered by the eROSITA telescope onboard the SRG...  相似文献   

Medium-Resolution Optical Range Space Images: Consumer Expectations     

Selin  V. A.  Emelyanov  A. A.  Sizov  O. S.  Emelyanov  K. S.  Borisov  A. V. 《Izvestiya Atmospheric and Oceanic Physics》2020,56(9):1182-1189

Izvestiya, Atmospheric and Oceanic Physics - Our survey of various space image consumers identified that the geographic coverage, regularity, and frequency of observations are the most important...  相似文献   

Photopolarimetric observations of the sample of polar candidates     

N. V. Borisov  M. M. Gabdeev  V. L. Afanasiev 《Astrophysical Bulletin》2016,71(1):95-100

We presented the first polarimetric observations of five cataclysmic variables: MTDra, 1RXSJ184542.4+483134, CRTSCSS081231 J071126+440405, IPHASJ052832.69+283837.6, and CRTSCSS130604 J215427+155714. Observations in the V band have shown that all the objects are highly circularly polarized. All the objects except the last one change the polarization sign during the orbital period. The object 1RXSJ184542.4+483134 was observed in two brightness states in 2011 and 2012. The brightness decrease of the systemwas accompanied by the increase of the amplitude of circular polarization variation.  相似文献   

C-Band Radiometer for Continuum Observations at RATAN-600 Radio Telescope     

P. G. Tsybulev  N. A. Nizhelskii  M. V. Dugin  A. N. Borisov  D. V. Kratov  R. Yu. Udovitskii 《Astrophysical Bulletin》2018,73(4):494-500

We describe the development of the tools and methods of 4.7-GHz band observations on RATAN-600 radio telescope and present a new design solution—a radiometric unit, and the development of an uncooled tuned receiver based on this unit and meant for operating in the “total power” radiometer mode.We discuss the design of the radio unit and the specificities of the radiometer design.We demonstrate the possibility of conducting observations in the total power radiometer mode at the theoretical sensitivity on time scales up to 10 seconds. The sensitivity of such a radiometer remains higher than that of a Dicke radiometer on time scales up to 100 seconds.  相似文献   

Distribution of anthropogenic radionuclides in the surface waters of the Indian Ocean in 2006–2009     

O. V. Stepanets  A. P. Borisov  A. N. Ligaev  A. V. Travkina  G. Yu. Solov’eva  B. S. Shmel’kov 《Geochemistry International》2011,49(6):618-627

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Effects of melt composition on Fe3+/Fe2+ in silicate melts: a step to model ferric/ferrous ratio in multicomponent systems     

Alexander Borisov  Harald Behrens  Francois Holtz 《Contributions to Mineralogy and Petrology》2015,169(2):1-12

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Accurate Calculation of Geodetic Heights of a Celestial Body’s Surface Points Relative to the Triaxial Ellipsoid     

Fleis  M. E.  Nyrtsov  M. V.  Borisov  M. M.  Sokolov  A. I. 《Doklady Earth Sciences》2019,486(2):663-668

Doklady Earth Sciences - The approximation of the Earth’s physical surface by a mathematical surface is commonly carried out by a sphere or an ellipsoid of revolution. A triaxial ellipsoid...  相似文献