共查询到20条相似文献，搜索用时 109 毫秒
1.
Osman M. Kamel 《Earth, Moon, and Planets》1989,44(3):275-289
We explain how the first step of Hori-Lie procedure is applied in general planetary theory to eliminate short-period terms. We extend the investigation to the third-order planetary theory. We solved the canonical equations of motion for secular and periodic perturbations by this method, and obtained the first integrals of the system of canonical equations. Also we showed the relation between the determining function in the sense of Hori and the determining function in the sense of Von Zeipel. 相似文献
2.
Monte Carlo simulations can either be viewed as a numerical method for solving evolutionary equations or as a way for statistically modelling the outcome of chaotic dynamical systems. Thus they are well suited for treating many aspects of cometary dynamics. We present a critical review of past applications of Monte Carlo simulations for both long- and short-period comets indicating the strength and weaknesses of the methods with suggestions for future applications. 相似文献
3.
C. Beaugé 《Celestial Mechanics and Dynamical Astronomy》1997,68(4):283-303
In this paper we study the effects of short-period perturbations in the planar asteroidal problem with Stokes drag. The averaging
of the dissipative terms is extended to show the appearance of crossed-terms which, in most commensurabilities, are more important
than several zeroth-order terms calculated in previous works.
In the case of resonance trapping in a libration point, we also discuss the effects of the eccentricity of the perturber in
the stationary solution. For the so-called ‘universal eccentricity’, we show that the contributions due to both, short-period
terms and harmonics of the auxiliary resonant angle, lead to a corrected value which is no longer invariant. The most significant
dependence of this new librational eccentricity is with the eccentricity of the perturber, although a slight variation is
also noted with respect to the chosen drag coefficient.
In all cases, we present comparisons with numerical simulations of the exact N-body equations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
A theory is developed for the perturbations to the orbit of a spherically symmetric satellite which accounts for the changes in the perigee and nodal positions and the variations of the Sun-Earth distance and direction over an orbital revolution. The theory is semi-analytical, the equations of motion being integrated with respect to time over the sunlit period of each orbital revolution. Long-periodic and short-periodic perturbations may be treated separately, and this is important for long-term analyses in terms of mean elements where short-period terms are averaged or omitted. 相似文献
5.
Giorgio E. O. Giacaglia James P. Murphy Theodore L. Felsentreger 《Celestial Mechanics and Dynamical Astronomy》1970,3(1):3-66
A semi-analytical solution to the problem of the motion of a satellite of the moon is presented. Perturbative effects which are considered include those due to the attraction of the moon, earth, and sun, the non-sphericity of the moon's gravitational field, coupling of lower-order terms, solar radiation pressure, and physical libration. Short-period terms and intermediate-period terms, terms with the period of the moon's longitude, are produced by means of von Zeipel's method; it is proposed to obtain the secular perturbations, and those depending only on the argument of perilune, by numerical integration of the equations of motions. The short-period terms and intermediate-period terms are developed up to second order, where first order is 10–2. The secular perturbations and perturbations dependent on the argument of perilune are obtained to third order. 相似文献
6.
Nikolaos Georgakarakos 《Monthly notices of the Royal Astronomical Society》2009,392(3):1253-1263
In a series of papers, we developed a technique for estimating the inner eccentricity in hierarchical triple systems, with the inner orbit being initially circular. However, for certain combinations of the masses and the orbital elements, the secular part of the solution failed. In this paper, we derive a new solution for the secular part of the inner eccentricity, which corrects the previous weakness. The derivation applies to hierarchical triple systems with coplanar and initially circular orbits. The new formula is tested numerically by integrating the full equations of motion for systems with mass ratios from 10−3 to 103 . We also present more numerical results for short-term eccentricity evolution, in order to get a better picture of the behaviour of the inner eccentricity. 相似文献
7.
We present photometric analysis of 8 short-period eclipsing binaries discovered and observed at Astronomical Observatory at Kolonica Saddle between 2007 and 2010 with different instruments. We determined their orbital periods and performed photometric analysis of their light curves. We found that 3 systems are detached binaries, 4 systems are over-contact binaries of W UMa type and one system is semi-detached with the secondary component filling its Roche lobe. Light curves of 2 systems exhibit asymmetries, explained by spot(s) on the surface of the components. 相似文献
8.
V.V. Emel’yanenko 《Earth, Moon, and Planets》2005,97(3-4):341-351
The origin of Jupiter-family comets is linked to the intermediate stage of evolution through the Centaur region. Thus the structure of the Centaur population provides important constraints on sources of short-period comets. We show that our model of the Oort cloud evolution gives results which are consistent with the orbital distribution of observed Centaurs. In particular, it explains the existence of the large population of Centaurs with semimajor axes greater than 60 AU. The main source for these objects is the inner Oort cloud. Both Jupiter-family and Halley-type comets are produced by Centaurs originating from the Oort cloud. The injection rate for Jupiter-family comets coming from the inner Oort cloud is, at least, not less than that for a model based on the observed sample of high-eccentricity trans-Neptunian objects. 相似文献
9.
Nikolaos Georgakarakos 《Monthly notices of the Royal Astronomical Society》2006,366(2):566-574
In previous papers, we developed a technique for estimating the inner eccentricity in hierarchical triple systems, with the inner orbit being initially circular. We considered systems with well-separated components and different initial setups (e.g., coplanar and non-coplanar orbits). However, the systems we examined had comparable masses. In the present paper, the validity of some of the formulae derived previously is tested by numerically integrating the full equations of motion for systems with smaller mass ratios (from 10−3 to 103 , i.e. systems with Jupiter-sized bodies). There is also discussion about HD 217107 and its planetary companions. 相似文献
10.
We eliminate by the method of von Zeipel the short-period terms in a first order-with respect to planetary masses—general planetary Uranus-Neptune theory. We exclude in the expansion terms of eccentricities and sines of inclinations higher than the third power.Our variables are the Poincaré canonical variables. We use the Jacobi-Radau set of origins, and we refer the planes of the osculating ellipses to a common fixed plane, the longitudes to a common origin. The short-periodic terms arising from the indirect and principal parts of the disturbing functions, are eliminated separately. The Fourier series of the principal part of the disturbing function, is reduced to the sum of only the first three terms. 相似文献
11.
Using improved, up-to-date stellar input physics tested against observations of low-mass stars and brown dwarfs, we calculate the secular evolution of low-mass donor cataclysmic variables (CVs), including those that form with a brown-dwarf donor. Our models confirm the mismatch between the calculated minimum period ( P min 70 min) and the observed short-period cut-off (80 min) in the CV period histogram. We find that tidal and rotational corrections applied to the one-dimensional stellar structure equations have no significant effect on the period minimum. Theoretical period distributions synthesized from our model sequences always show an accumulation of systems at the minimum period, a feature absent from the observed distribution. We suggest that non-magnetic CVs become unobservable as they are effectively trapped in permanent quiescence before they reach P min , and that small-number statistics may hide the period spike for magnetic CVs. 相似文献
12.
Alejandro Lara Andrea Borgazzi Odim Jr. Mendes Reinaldo R. Rosa Margarete Oliveira Domingues 《Solar physics》2008,248(1):155-166
We have constructed a time series of the number of coronal mass ejections (CMEs) observed by SOHO/LASCO during solar cycle
23. Using spectral analysis techniques (the maximum entropy method and wavelet analysis) we found short-period (< one year)
semiperiodic activity. Among others, we found interesting periodicities at 193, 36, 28, and 25 days. We discuss the implications
of such short-period activity in terms of the emergence and escape of magnetic flux from the convection zone, through the
low solar atmosphere (where these periodicities have been found for numerous activity parameters), toward interplanetary space.
This analysis shows that CMEs remove the magnetic flux in a quasiperiodic process in a way similar to that of magnetic flux
emergence and other solar eruptive activity. 相似文献
13.
Tidal friction in triple stars 总被引：1，自引：0，他引：1
L. G. Kiseleva P. P. Eggleton & S. Mikkola 《Monthly notices of the Royal Astronomical Society》1998,300(1):292-302
Tidal friction in close binaries, with periods of a few days, is expected to circularize the orbit on a time-scale long compared with human observation but shorter than, or comparable to, the lifetimes of main-sequence stars. In a hierarchical triple star, however, the perturbing effect of the distant third star may decircularize the inner orbit significantly on a time-scale of the order of days (as in λ Tau) or centuries (as in β Per). If the inner pair is observed to be semidetached, however, it is plausible to assume that the eccentricity is small. This may be because tidal friction is operating on a comparably short time-scale, and so it is in principle amenable to observation. We attempt to determine a lower limit to the strength of tidal friction in λ Tau and β Per, on the basis of this consideration. Tidal friction will also lead to a secular transfer of angular momentum from the inner orbit to the outer orbit. Too rapid a transfer may lead to orbital shrinkage that is fast compared with the nuclear time-scales of the inner systems, and this can also be ruled out on observational grounds. Thus we may be able to set an upper as well as a lower limit to the strength of tidal friction, on the basis of observations. In a young hierarchical triple, provided that the orbits are fairly nearly orthogonal, tidal friction can serve to reduce the inner orbital period from months to days within a fairly short period of time, of order P 2 out / P in . This may be a significant mechanism for producing young short-period binaries. 相似文献
14.
V. P. Tomanov 《Kinematics and Physics of Celestial Bodies》2007,23(5):196-206
We analyze our earlier data on the numerical integration of the equations of motion for 274 short-period comets (with the period P<200 yr) on a time interval of 6000 yr. As many as 54 comets had no close approaches to planets, 13 comets passed through the Saturnian sphere of action, and one comet passed through the Uranian sphere of action. The orbital elements of these 68 comets changed by no more than ±3 percent in a space of 6000 yr. As many as 206 comets passed close to Jupiter. We confirm Everhart’s conclusion that Jupiter can capture long-period comets with q = 4–6 AU and i < 9° into short-period orbits. We show that nearly parabolic comets cross the solar system mainly in the zone of terrestrial planets. No relationship of nearly parabolic comets and terrestrial planets was found for the epoch of the latest apparition of comets. Guliev’s conjecture about two trans-Plutonian planets is based on the illusory excess of cometary nodes at large heliocentric distances. The existence of cometary nodes at the solar system periphery turns out to be a solely geometrical effect. 相似文献
15.
We propose a mixed analytical and numerical method as a practical means of solving the perturbation equations based on Vinti's intermediate orbit. Hori's averaging method is used to define mean elements σ* and short-period perturbations Δσs. Δσs accurate to the third-orbit, are found by Fourier analysis, and dσ*/dt, accurate to the fourth order, from numerical averaging. The present procedure can be used to reduce satellite laser observations with a high precision. 相似文献
16.
J. P. S. Carvalho R. Vilhena de Moraes A. F. B. A. Prado 《Celestial Mechanics and Dynamical Astronomy》2010,108(4):371-388
In this paper we present an analytical theory with numerical simulations to study the orbital motion of lunar artificial satellites.
We consider the problem of an artificial satellite perturbed by the non-uniform distribution of mass of the Moon and by a
third-body in elliptical orbit (Earth is considered). Legendre polynomials are expanded in powers of the eccentricity up to
the degree four and are used for the disturbing potential due to the third-body. We show a new approximated equation to compute
the critical semi-major axis for the orbit of the satellite. Lie-Hori perturbation method up to the second-order is applied
to eliminate the terms of short-period of the disturbing potential. Coupling terms are analyzed. Emphasis is given to the
case of frozen orbits and critical inclination. Numerical simulations for hypothetical lunar artificial satellites are performed,
considering that the perturbations are acting together or one at a time. 相似文献
17.
Brian Jackson Emily Jensen Sarah Peacock Phil Arras Kaloyan Penev 《Celestial Mechanics and Dynamical Astronomy》2016,126(1-3):227-248
Many gaseous exoplanets in short-period orbits are on the verge or are in the process of Roche-lobe overflow (RLO). Moreover, orbital stability analysis shows tides can drive many hot Jupiters to spiral inevitably toward their host stars. Thus, the coupled processes of orbital evolution and RLO likely shape the observed distribution of close-in exoplanets and may even be responsible for producing some of the short-period rocky planets. However, the exact outcome for an overflowing planet depends on its internal response to mass loss, and the accompanying orbital evolution can act to enhance or inhibit RLO. In this study, we apply the fully-featured and robust Modules for Experiments in Stellar Astrophysics suite to model RLO of short-period gaseous planets. We show that, although the detailed evolution may depend on several properties of the planetary system, it is largely determined by the core mass of the overflowing gas giant. In particular, we find that the orbital expansion that accompanies RLO often stops and reverses at a specific maximum period that depends on the core mass. We suggest that RLO may often strand the remnant of a gas giant near this orbital period, which provides an observational prediction that can corroborate the hypothesis that short-period gas giants undergo RLO. We conduct a preliminary comparison of this prediction to the observed population of small, short-period planets and find some planets in orbits that may be consistent with this picture. To the extent that we can establish some short-period planets are indeed the remnants of gas giants, that population can elucidate the properties of gas giant cores, the properties of which remain largely unconstrained. 相似文献
18.
Robert A. Howland Jr 《Celestial Mechanics and Dynamical Astronomy》1977,15(3):327-352
A new technique is developed for the formal solution of non-degenerate or degenerate Hamiltonian systems under periodic perturbation through continually accelerated elimination of the periodic terms. Special features of the method are the ability to eliminate both short-period and longperiod variables simultaneously and the attainment of [formal] quadratic convergence for non-degenerate systems and nearly quadratic convergence in degenerate cases. The technique utilizes Lie transforms and is based on an approach due to Kolmogorov and Arnol'd. 相似文献
19.
《天文和天体物理学研究(英文版)》2015,(5)
We report the results of a search for variable stars in the open cluster NGC 2141. Ten variable stars are detected, among which nine are new variable stars and they are classified as three short-period W UMa-type eclipsing binaries, two EAtype eclipsing binaries, one EB-type eclipsing binary, one very short-period RS CVntype eclipsing binary, one d-type RR Lyrae variable star, and one unknown type of variable star. The membership and physical properties are discussed, based on their light curves, positions in the color magnitude diagrams, spatial locations and periods.A known EB-type eclipsing binary is also identified as a blue straggler candidate in the cluster. Furthermore, we find that all eclipsing contact binaries have prominent asymmetric eclipses and display the O'Connell effect, which increases with a decrease in orbital periods. This suggests that the O'Connell effect is probably related to the evolution of the orbital period in short period eclipsing binary systems. 相似文献
20.
This study concerns the long-term monitoring of the secular variation character in the orbital period of some short-period eclipsing binaries observed at the Ankara University Observatory. Among the systems of our observing list are CK Boo, V502 Oph and V836 Cyg that show long-term secular variations in their orbital periods. We use classical O-C diagram analysis technique as a tool to reveal the character of the period variations of these binary systems. 相似文献