The Investigation of Optical Variability on Time Scales of 10-7-102S: Hardware, Software, Results     

G.M. Beskin  V.N. Komarova  S.I. Neizvestny  V.L. Plokhotnichenko  M.Yu. Popova  A.V. Zhuravkov 《Experimental Astronomy》1997,7(4):413-420

We present a hardware/software complex for photometric observations with high time resolution. The hardware consists of a detector, a recording system which is a "time - coded" converter, a PC/AT 486 computer and a tape recorder. As a detector we can use any device that provides its output in such a way that for every detected quantum there is a correspondent standard impulse with additional information on the quantum - space coordinates, frequency, polarization, etc. A special "time - coded" converter "Quantochron" registers the quanta arrival times with an accuracy of ± 20 nanoseconds stores in the computer the 16-bit codes as well as the 16-bit codes of additional information. At present, the photometer complex allows to register without distortion the flux events up to 380 kHz. We describe the special methods and software capable of searching and analyzing any type of photon flux intensity variations. The results of the high time resolution investigations of a number of relativistic and fast variable objects, such as black hole candidates, LMXB, pulsars and flare stars, are presented.  相似文献   

The isotopic–geochronological age of trap formation rocks in the sedimentary section of the Baikit anteclise     

K. S. Alekseeva  L. P. Popova  A. V. Postnikov  O. V. Postnikova 《Doklady Earth Sciences》2016,470(2):1014-1018

The Lower Cambrian Usol’e Formation in the Kamov arch of the Baikit anteclise includes stratiform intrusions confined to several levels. According to isotopic?geochronological investigations, the age of stratiform intrusions composed of olivine dolerites is estimated to be 256.0 ± 3.2 Ma.  相似文献   

Behavior of lanthanides during the formation of the Svetloe deposit,Chukotka     

Yu. A. Popova  A. Yu. Bychkov  S. S. Matveeva 《Geochemistry International》2016,54(8):732-738

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On possible circumbinary configurations of the planetary systems of α Centauri and EZ Aquarii     

E. A. Popova  I. I. Shevchenko 《Astronomy Letters》2016,42(4):260-267

Possible configurations of the planetary systems of the binary stars α Cen A–BandEZAqr A–C are analyzed. The P-type orbits—circumbinary ones, i.e., the orbits around both stars of the binary, are studied. The choice of these systems is dictated by the fact that α Cen is closest to us in the Galaxy, while EZ Aqr is the closest system whose circumbinary planets, as it turns out, may reside in the “habitability zone.” The analysis has been performed within the framework of the planar restricted three-body problem. The stability diagrams of circumbinary motion have been constructed: on representative sets of initial data (in the pericentric distance–eccentricity plane), we have computed the Lyapunov spectra of planetary motion and identified the domains of regular and chaotic motion through their statistical analysis. Based on present views of the dynamics and architecture of circumbinary planetary systems, we have determined the most probable planetary orbits to be at the centers of the main resonance cells, at the boundary of the dynamical chaos domain around the parent binary star, which allows the semimajor axes of the orbits to be predicted. In the case of EZ Aqr, the orbit of the circumbinary planet is near the habitability zone and, given that the boundary of this zone is uncertain, may belong to it.  相似文献   

Determination of the height of the “meteoric explosion”     

V.?V.?ShuvalovEmail author  O.?P.?Popova  V.?V.?Svettsov  I.?A.?Trubetskaya  D.?O.?Glazachev 《Solar System Research》2016,50(1):1-12

When cosmic bodies of asteroidal and cometary origin, with a size from 20 to approximately 100 m, enter dense atmospheric layers, they are destroyed with a large probability under the action of aerodynamic forces and decelerated with the transfer of their energy to the air at heights from 20–30 to several kilometers. The forming shock wave reaches the Earth’s surface and can cause considerable damage at great distances from the entry path similar to the action of a high-altitude explosion. We have performed a numerical simulation of the disruption (with allowance for evaporation of fragments) and deceleration of meteoroids having the aforesaid dimensions and entering the Earth’s atmosphere at different angles and determined the height of the equivalent explosion point generating the same shock wave as the fall of a cosmic body with the given parameters. It turns out that this height does not depend on the velocity of the body and is approximately equal to the height at which this velocity is reduced by half. The obtained results were successfully approximated by a simple analytical formula allowing one to easily determine the height of an equivalent explosion depending on the dimensions of the body, its density, and angle of entry into the atmosphere. A comparison of the obtained results with well-known approximate analytical (pancake) models is presented and an application of the obtained formula to specific events, in particular, to the fall of the Chelyabinsk meteorite on February 15, 2013, and Tunguska event of 1908, is discussed.  相似文献   

Relation between sudden increases in the solar wind dynamic pressure,auroral proton flashes,and geomagnetic pulsations in the Pc1 range     

T. A. Popova  A. G. Yahnin  T. A. Yahnina  H. Frey 《Geomagnetism and Aeronomy》2010,50(5):568-575

The interrelation between sudden increases in the solar wind dynamic pressure, auroral proton flashes on the dayside equatorward of the oval, and geomagnetic pulsations in the Pc1 range is considered on the basis of simultaneous observations of the solar wind plasma parameters, proton auroras on the IMAGE satellite, and geomagnetic pulsations at the Lovozero Observatory. It is indicated that proton luminosity flashes were observed in 70% of cases equatorward of the auroral oval during sudden changes in the solar wind pressure. In this case, flashes of proton auroras were observed in 85% of cases during sudden changes in the pressure, which were related to interplanetary shocks. Increases in pressure during tangential discontinuities were accompanied by flashes of proton auroras only in 45% of cases. When the ground station was conjugate to the region occupied by a proton aurora flash, the appearance or intensification of existent pulsations in the Pc1 range was observed in 96% of cases. When the ground station was not conjugate to the region of a proton luminosity flash, the response in geomagnetic pulsations was observed in 32% of events. When a sudden change in the solar wind pressure was not accompanied by a proton luminosity flash, the response in pulsations in the Pc1 range was hardly observed.  相似文献   

Binaries in the vicinity of the open cluster IC 4665.I. V 378 Oph     

Z. Kraicheva  M. Popova  A. Antov 《Astronomische Nachrichten》1989,310(3):227-230

Erste Ergebnisse unseres Programms zur Untersuchung von Doppelsternen, die mögliche Mitglieder von offenen Sternhaufen sind, werden vorgestellt. Daneben wurde die Verteilung von spektroskopischen Variablen und Bedeckungsveränderlichen in der weiteren Umgebung des offenen Haufens IC 4665 ermittelt. Desweiteren wird über eine photometrische Studie des Variablen V 378 Oph berichtet. Über dieses Objekt gibt es, den Helligkeitswechsel betreffend, widersprüchliche Daten. Unsere Beobachtungen bestätigen, daß V 378 Oph ein Doppelstern vom Typ ß Lyrae ist. Seine Periode wurde bestimmt und eine mittlere Lichtkurve ermittelt. Es wird auf einige Besonderheiten hingewiesen, die zusätzliche lichtelektrische und photometrische Beobachtungen erfordern. Anschließend wird diskutiert, ob V 378 Oph zu Mel 186 (Cr 359) oder IC 4665 gehört.  相似文献   

Simulating pathways of subsurface oil in the Faroe–Shetland Channel using an ocean general circulation model     

C.E. Main  A. Yool  N.P. Holliday  E.E. Popova  D.O.B. Jones  H.A. Ruhl 《Marine pollution bulletin》2017,114(1):315-326

Little is known about the fate of subsurface hydrocarbon plumes from deep-sea oil well blowouts and their effects on processes and communities. As deepwater drilling expands in the Faroe–Shetland Channel (FSC), oil well blowouts are a possibility, and the unusual ocean circulation of this region presents challenges to understanding possible subsurface oil pathways in the event of a spill. Here, an ocean general circulation model was used with a particle tracking algorithm to assess temporal variability of the oil-plume distribution from a deep-sea oil well blowout in the FSC. The drift of particles was first tracked for one year following release. Then, ambient model temperatures were used to simulate temperature-mediated biodegradation, truncating the trajectories of particles accordingly. Release depth of the modeled subsurface plumes affected both their direction of transport and distance travelled from their release location, and there was considerable interannual variability in transport.  相似文献   

Asteroid Apophis: Evaluating the impact hazards of such bodies     

V. V. Shuvalov  V. V. Svettsov  N. A. Artem’eva  I. A. Trubetskaya  O. P. Popova  D. O. Glazachev 《Solar System Research》2017,51(1):44-58

Soon after the discovery of asteroid 99942 Apophis, it was classified as a potentially hazardous object with a high probability of an impact on the Earth in 2029. Although subsequent observations have substantially reduced the probability of a collision, it has not been ruled out; moreover, similar-sized asteroids in orbits intersecting the Earth’s orbit may well be discovered in the near future. We conduct a numerical simulation of an atmospheric passage and an impact on the Earth’s surface of a stony cosmic body with a diameter of 300 m and kinetic energy of about 1000 Mt, which roughly corresponds to the parameters of the asteroid Apophis, at atmospheric entry angles of 90° (vertical stroke), 45°, and 30°. The simulation is performed by solving three-dimensional equations of hydrodynamics and radiative transfer equations in the approximations of radiative heat conduction and volume emission. The following hazards are considered: an air shock wave, ejecta from the crater, thermal radiation, and ionospheric disturbances. Our calculations of the overpressure and wind speed on the Earth’s surface show that the zone of destruction of the weakest structures can be as large as 700–1000 km in diameter; a decrease in the flight path angle to the surface leads to a marked increase in the area affected by the shock wave. The ionospheric disturbances are global in nature and continue for hours: at distances of several thousand kilometers at altitudes of more than 100 km, air density disturbances are tens of percent and the vertical and horizontal velocity components reach hundreds of meters per second. The impact of radiation on objects on the Earth’s surface is estimated by solving the equation of radiative transfer along rays passing through a luminous area. In clear weather, the size of the zone where thermal heating may ignite wood can be as large as 200 km, and the zone of individual fire outbreaks associated with the ignition of flammable materials can be twice as large. In the 100-km central area, which is characterized by very strong thermal damage, there is ignition of structures, roofs, clothes, etc. The human hazardous area increases with the decrease in the trajectory angle, and people may experience thermal effects at distances of up to 250–400 km from the crater.  相似文献   

Circumbinary Planetary Systems in the Solar Neighborhood: Stability and Habitability     

Shevchenko  I. I.  Melnikov  A. V.  Popova  E. A.  Bobylev  V. V.  Karelin  G. M. 《Astronomy Letters》2019,45(9):620-626

Astronomy Letters - The radii of the inner and outer boundaries of the circumbinary habitable zone (CBHZ) and the radii of the circumbinary chaotic zone (CBCZ) have been calculated for close binary...  相似文献