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1.
In an earlier paper Arp, Bi, Chu and Zhu investigated various quasar samples and recognized a periodicity of remarkable degree in them. Their conclusion was that the existence of such a periodicity is a counterevidence against the cosmological origin of quasar redshifts. Since this question is of great importance in a cosmological context, here we reanalyze some of the samples together with a galaxy sample of the pencil-beam survey of Broadhurstet al. Our result is that on the plane of cosmological parameters (0, 0) there is a non-negligible region where two quasar samples and the galaxy sample are simultaneously fairly periodic. Pure periodicity is still compatible with cosmological principles, at least on length scales much longer than the period length. So the regularities can fit into a cosmological context. 相似文献
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3.
S. A. Borysenko Yu. V. Sizonenko I. V. Luk’yanyk A. V. Ivanova A. D. Voitsekhovskaya T. P. Sergeeva A. V. Golovin 《Kinematics and Physics of Celestial Bodies》2011,27(2):92-97
Photometric measurements of photographic images of comet C/1987 P1 Bradfield have been carried out with a flat-bed scanner
equipped with a slide module. Lengthwise and transverse photometric profiles of the cometary plasma tail have been obtained.
Magnetic field induction and some other physical characteristics of the cometary plasma tail observed in November 1987 have
been estimated with the use of the diffusion model for a cometary tail by Shul’man and Nazarchuk (1968). It has been shown
that the scanned images of comets can be used for estimating the physical characteristics of cometary tails. 相似文献
4.
L. G. Luk’yanov 《Astronomy Letters》2005,31(8):563-568
We consider the conservative two-body problem with a constant total mass, but with variable individual masses. The problem is shown to be completely integrable for any mass variation law. The Keplerian motion known for the classical two-body problem with constant masses remains valid for the relative motion of the bodies. The absolute motions of the bodies depend on the center-of-mass motion. Hitherto unknown quadratures that depend on the mass variation law were derived for the integrals of motion of the center of mass. We consider some of the laws that are of interest in studying the motion of close binary stars with mass transfer. 相似文献
5.
Réka?LukácsEmail author Szabolcs?Harangi Olivier?Bachmann Marcel?Guillong Martin?Dani?ík Yannick?Buret Albrecht?von?Quadt István?Dunkl László?Fodor Jakub?Sliwinski Ildikó?Soós János?Szepesi 《Contributions to Mineralogy and Petrology》2015,170(5-6):52
A silicic ignimbrite flare-up episode occurred in the Pannonian Basin during the Miocene, coeval with the syn-extensional period in the region. It produced important correlation horizons in the regional stratigraphy; however, they lacked precise and accurate geochronology. Here, we used U–Pb (LA-ICP-MS and ID-TIMS) and (U–Th)/He dating of zircons to determine the eruption ages of the youngest stage of this volcanic activity and constrain the longevity of the magma storage in crustal reservoirs. Reliability of the U–Pb data is supported by (U–Th)/He zircon dating and magnetostratigraphic constraints. We distinguish four eruptive phases from 15.9 ± 0.3 to 14.1 ± 0.3 Ma, each of which possibly includes multiple eruptive events. Among these, at least two large volume eruptions (>10 km3) occurred at 14.8 ± 0.3 Ma (Demjén ignimbrite) and 14.1 ± 0.3 Ma (Harsány ignimbrite). The in situ U–Pb zircon dating shows wide age ranges (up to 700 kyr) in most of the crystal-poor pyroclastic units, containing few to no xenocrysts, which implies efficient recycling of antecrysts. We propose that long-lived silicic magma reservoirs, mostly kept as high-crystallinity mushes, have existed in the Pannonian Basin during the 16–14 Ma period. Small but significant differences in zircon, bulk rock and glass shard composition among units suggest the presence of spatially separated reservoirs, sometimes existing contemporaneously. Our results also better constrain the time frame of the main tectonic events that occurred in the Northern Pannonian Basin: We refined the upper temporal boundary (15 Ma) of the youngest counterclockwise block rotation and the beginning of a new deformation phase, which structurally characterized the onset of the youngest volcanic and sedimentary phase. 相似文献
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Lukáš Ackerman Gordon Medaris Jr. Petr Špaček Jaromír Ulrych 《International Journal of Earth Sciences》2015,104(8):1957-1979
8.
Roman Skála Jaromír Ulrych Lukáš Ackerman Emil Jelínek Jaroslav Dostál Ernst Hegner Zdeněk Řanda 《International Journal of Earth Sciences》2014,103(5):1233-1262
The ?eské st?edoho?í Mts. is the dominant volcanic center of the Oh?e (Eger) rift zone. It hosts the Roztoky Intrusive Complex (RIC), which is made up of a caldera vent and intrusions of 33–28-Ma-old hypabyssal bodies of essexite–monzodiorite–sodalite syenite series accompanied by a radially oriented 30–25-Ma-old dike swarm comprising about 1,000 dikes. The hypabyssal rocks are mildly alkaline mostly foid-bearing types of mafic to intermediate compositions. The dike swarm consists of chemically mildly alkaline and rare strongly alkaline rocks (tinguaites). The geochemical signatures of the mildly alkaline hypabyssal and associated dike rocks of the RIC are consistent with HIMU mantle sources and contributions from lithospheric mantle. The compositional variations of essexite and monzodiorite can be best explained by fractional crystallization of parent magma without significant contributions of crustal material. On the other hand, the composition of monzosyenite, leuco-monzodiorite and sodalite syenite reflects fractional crystallization coupled with variable degrees of crustal assimilation. It is suggested that the parent magmas in the Oh?e rift were produced by an adiabatic decompression melting of ambient upper mantle in response to lithospheric extension associated with the Alpine Orogeny. 相似文献
9.
Field infiltration tests using portable rainfall infiltrometers were conducted in the Wangjiagou experimental basin in the hilly loess region of north China. Based on data collected at 27 sites, a topographic zonation of infiltration characteristics was observed. The average steady infiltration rate and the average ponding time decreased from the hilltop to the hillslope and further decreased to the gully wall. Such a zonation is closely related to the variations of topography, soil and land use conditions in the study area. A general infiltration model is proposed. Collected field data are used to establish the applicability of the proposed model in the study area. 相似文献
10.
We report exceptional fireball activity of the Orionid meteor shower in 2006. During four nights in October 2006 the autonomous
fireball observatories of the Czech part of the European Fireball Network (EN) recorded 48 fireballs belonging to the Orionids.
This is significantly more than the total number of Orionids recorded during about five decades long continuous operation
of the EN. Based on precise multi-station photographic and radiometric data we present accurate atmospheric trajectories,
heliocentric orbits, light curves and basic physical properties of 10 Orionid fireballs with atmospheric trajectories that
were long enough and, with one exception, were observed from at least three stations. Seven were recorded in within a 2-h
interval in the night of 20/21 October. Their basic parameters such as radiant positions and heliocentric orbits are very
similar. This high fireball activity originated from a very compact geocentric radiant defined by α = 95.10° ± 0.10° and
δ = 15.50° ± 0.06°. These fireballs most likely belonged to a distinct filament of larger meteoroids trapped in 1:5 resonance
with Jupiter. From detailed light curves and basic fireball classification we found that these meteoroids appertain to the
weakest component of interplanetary matter. 相似文献