共查询到20条相似文献，搜索用时 46 毫秒
1.
Christopher Stagg 《Celestial Mechanics and Dynamical Astronomy》1984,32(4):365-370
In the restricted problem of three bodies, it has been discovered that, in a nonrotating frame, almost perfectly square orbits can result. Numerical investigations of these orbits have been made, and a brief explanation of their behaviour is given. 相似文献
2.
E. N. Slyuta 《Solar System Research》2014,48(3):217-238
The morphometric parameters are examined for the shape of fragments of ordinary chondrites, iron meteorites, S- and C-class stony asteroids, metallic asteroids, and icy small bodies of the Solar System. All small Solar System bodies are shown to have, depending on their composition and, hence, physical and mechanical properties, a specific shape that is unique to a given composition. C-class asteroids, the strength of which is almost three times less than that of S asteroids, differ from the latter in their less elongated shape. No systematic change is observed in the morphometric parameters (increased roundness or sphericity) of small bodies of differing compositions depending on their mass, which suggests that the hypothesis of creep in small Solar System bodies is unlikely to be true. The absence of creep confirms that, regardless of their composition, all small Solar System bodies are solid elastic bodies having an ultimate strength (tensile strength and compressive strength) and a yield strength. 相似文献
3.
S. M. El-Shaboury 《Astrophysics and Space Science》1990,174(1):151-154
The restricted problem of three bodies with variable masses is considered. It is assumed that the infinitesimal body is axisymmetric with constant mass and the finite bodies are spherical with variable masses such that the ratio of their masses remains constant. The motion of the finite bodies are determined by the Gyldén-Meshcherskii problem. It is seen that the collinear, triangular, and coplanar solutions not exist, but these solutions exist when the infinitesimal body be a spherical. 相似文献
4.
V. Szebehely 《Celestial Mechanics and Dynamical Astronomy》1973,8(2):163-167
The gravitational problem of three bodies is treated in the case when the masses of the participating bodies are of the same order of magnitude and their distances are arbitrary. Estimates for the minimum perimeter of the triangle formed by the bodies and for the rate of the expansion of the system are obtained from Sundman's modified general inequality when the total energy of the system is negative. These estimates are used to propose and to describe an escape mechanism based on genuine three-body dynamics and to offer a method to control the accuracy of numerical integrations of the problem of three bodies. The requirements for these two applications are contradictory since an escape is the consequence of a close triple approach which phenomenon is detrimental to the accuracy of the computations. Consequently, the numerical study of escape from a triple system must treat triple close approaches with high reliability.Presented at the Conference on Celestial Mechanics, Oberwolfach, Germany, August 27–September 2, 1972. 相似文献
5.
In this paper we have proved the existence of libration points for the generalised photogravitational restricted problem of three bodies. We have assumed the infinitesimal mass of the shape of an oblate spheroid and both of the finite masses to be radiating bodies and the effect of their radiation pressure on the motion of the infinitesimal mass has also been taken into account. It is seen that there is a possibility of nine libration points for small values of oblateness, three collinear, four coplanar and two triangular. 相似文献
6.
John D. Hadjidemetriou 《Astrophysics and Space Science》1976,40(1):201-224
Several families of the planar general three-body problem for fixed values of the three masses are found, in a rotating frame of reference, where the mass of two of the bodies is small compared to the mass of the third body. These families were obtained by the continuation of a degenerate family of periodic orbits of three bodies where two of the bodies have zero masses and describe circular orbits around a third body with finite mass, in the same direction.The above families represent planetary systems with the body with the large mass representing the Sun and the two small bodies representing two planets or comets. One section of a family is shown to represent the Jupiter family of comets and also a model for the Sun-Jupiter-Saturn system is found.The stability analysis revealed that stability exists for small masses and small eccentricities of the two planets. Planetary systems with relatively large masses and eccentricities are proved to be unstable. In particular, the Jupiter family of comets, for small masses of the two small bodies, and the Sun-Jupiter-Saturn system are proved to be stable. Also, it was shown that resonances are not necessarily associated with instabilities. 相似文献
7.
W. J. Robinson 《Celestial Mechanics and Dynamical Astronomy》1973,8(2):323-330
This paper is concerned with an extension of the classical restricted problem of three bodies in three dimensions. Usually, the satellite is considered to be a point mass. Here, the satellite is assumed to have a simple structure. The equations of motion are obtained and some of their consequences are discussed. 相似文献
8.
In the n-body problem a central configuration is formed if the position vector of each particle with respect to the center
of mass is a common scalar multiple of its acceleration vector. We consider the problem: given a collinear configuration of
four bodies, under what conditions is it possible to choose positive masses which make it central. We know it is always possible
to choose three positive masses such that the given three positions with the masses form a central configuration. However
for an arbitrary configuration of four bodies, it is not always possible to find positive masses forming a central configuration.
In this paper, we establish an expression of four masses depending on the position x and the center of mass u, which gives a central configuration in the collinear four body problem. Specifically we show that there is a compact region
in which no central configuration is possible for positive masses. Conversely, for any configuration in the complement of
the compact region, it is always possible to choose positive masses to make the configuration central. 相似文献
9.
Zdeněk Kopal 《Astrophysics and Space Science》1970,6(1):33-35
The observed fact that light changes of the asteroids exhibit no beat periods is interpreted as an indication that they do not wobble in space like spinning tops, but spin about only one axis (possibly — but not necessarily — inclined but little to the plane of their orbits). Since, moreover, the damping of three-dimensional rotation by jovi-solar attraction would require a time which is long in comparison with the age of the solar system, it is concluded that the present uni-axial rotation must represent a property preserved from the time when the asteroids were formed. This would seem to testify against their origin by collisional fragmentation of larger bodies; for in such a case the resulting solid splinters would still today be characterized by a random distribution of their angular momenta in three dimensions.The writer owes this assurance to Dr. Thomas Gehrels (private information). 相似文献
10.
We study planar central configurations of the five-body problem where three of the bodies are collinear, forming an Euler
central configuration of the three-body problem, and the two other bodies together with the collinear configuration are in
the same plane. The problem considered here assumes certain symmetries. From the three bodies in the collinear configuration,
the two bodies at the extremities have equal masses and the third one is at the middle point between the two. The fourth and
fifth bodies are placed in a symmetric way: either with respect to the line containing the three bodies, or with respect to
the middle body in the collinear configuration, or with respect to the perpendicular bisector of the segment containing the
three bodies. The possible stacked five-body central configurations satisfying these types of symmetries are: a rhombus with
four masses at the vertices and a fifth mass in the center, and a trapezoid with four masses at the vertices and a fifth mass
at the midpoint of one of the parallel sides. 相似文献
11.
Abstract– Eucrites, which are probably from 4 Vesta, and angrites are the two largest groups of basaltic meteorites from the asteroid belt. The parent body of the angrites is not known but it may have been comparable in size to Vesta as it retained basalts and had a core dynamo. Both bodies were melted early by 26Al and formed basalts a few Myr after they accreted. Despite these similarities, the impact histories of the angrites and eucrites are very different: angrites are very largely unshocked and none are breccias, whereas most eucrites are breccias and many are shocked. We attribute the lack of shocked and unbrecciated angrites to an impact, possibly at 4558 Myr ago—the radiometric age of the younger angrites—that extracted the angrites from their original parent body into smaller bodies. These bodies, which may have had a diameter of approximately 10 km, suffered much less impact damage than Vesta during the late heavy bombardment because small bodies retain shocked rocks less efficiently than large ones and because large bodies suffer near‐catastrophic impacts that deposit vastly more impact energy per kg of target. Our proposed history for the angrites is comparable to that proposed by Bogard and Garrison (2003) for the unbrecciated eucrites with Ar‐Ar ages of 4.48 Gyr and that for unbrecciated eucrites with anomalous oxygen isotopic compositions that did not come from Vesta. We infer that the original parent bodies of the angrites and the anomalous eucrites were lost from the belt when the giant planets migrated and the total mass of asteroids was severely depleted. Alternatively, their parent bodies may have formed in the terrestrial planet region and fragments of these bodies were scattered out to the primordial Main Belt as a consequence of terrestrial planet formation. 相似文献
12.
《Planetary and Space Science》2007,55(4):475-493
The backbone of the analysis in most dynamical systems is the study of periodic motions, since they greatly assist us to understand the structure of all possible motions. In this paper, we deal with the photogravitational version of the rectilinear restricted four-body problem and we investigate the dynamical behaviour of a small particle that is subjected to both the gravitational attraction and the radiation pressure of three bodies much bigger than the particle, the primaries. These bodies are always in syzygy and two of them have equal masses and are located at equal distances from the third primary. We study the effect of radiation on the distribution of the periodic orbits, their stability, as well as the evolution of the families and their main features. 相似文献
13.
David A. Minton 《Icarus》2008,195(2):698-704
Rubble pile asteroids can attain shapes that are dramatically different from those of rotating, self-gravitating equilibrium fluids. A new numerical technique, called “seed growth,” is demonstrated for calculating three-dimensional bodies that are self-gravitating and rotating, and whose every surface is approximately at a constant angle, ?, with respect to the local horizontal. By altering the configuration of cusps, which are points along a constant longitude path where the surface angle changes sign but not magnitude, multiple solution shapes that satisfy the condition that all surface slopes are at a constant angle are possible. Five different cusp configurations are explored here, three of which yield solutions for 20°???30°. Rotational effects are explored, and it is found that for some solution shapes, the ratios of their shortest to longest dimensions, c/a, can fall outside the limits published in the literature for rotating, cohesionless, spheroidal bodies. Solution shapes show some similarities to observed small bodies, such as the saturnian satellite Atlas, the near-Earth Asteroid 1999 KW4, and some contact binary asteroids. 相似文献
14.
P. C. Kammeyer 《Celestial Mechanics and Dynamical Astronomy》1983,30(4):329-342
In this paper the existence of families of symmetric periodic orbits in the rectilinear three body problem with the middle mass much larger than the masses on the outside is rigorously established. A number of these families are continued numerically and their stability properties as orbits of the planar general problem of three bodies are studied. 相似文献
15.
We present new irradiation experiments performed on the enstatite chondrite Eagle (EL6) and the mesosiderite Vaca Muerta. These experiments were performed with the aims of (a) quantifying the spectral effect of the solar wind on their parent asteroid surfaces and (b) identifying their parent bodies within the asteroid belt. For Vaca Muerta we observe a reddening and darkening of the reflectance spectrum with progressive irradiation, consistent with what is observed in the cases of silicates and silicate-rich meteorites such as OCs and HEDs. For Eagle we observe little spectral variation, and therefore we do not expect to observe a significant spectral difference between EC meteorites and their parent bodies. We evaluated possible parent bodies for both meteorites by comparing their VNIR spectra (before and after irradiation) with those of ∼400 main-belt asteroids. We found that 21 Lutetia (Rosetta's forthcoming fly-by target) and 97 Klotho (both Xc types in the new Bus-DeMeo taxonomy) have physical properties compatible with those of enstatite chondrite meteorites while 201 Penelope, 250 Bettina and 337 Devosa (all three are Xk types in the Bus-DeMeo taxonomy) are compatible with the properties of mesosiderites. 相似文献
16.
We consider the problem of the motion of a zero-mass body in the vicinity of a system of three gravitating bodies forming a central configuration.We study the case where two gravitating bodies of equal mass lie on the same straight line and rotate around the central body with the same angular velocity. Equations for calculating the equilibrium positions in this system have been derived. The stability of the equilibrium points for a system of three gravitating bodies is investigated. We show that, as in the case of libration points for two bodies, the collinear points are unstable; for the triangular points, there exists a ratio of the mass of the central body to the masses of the extreme bodies, 11.720349, at which stability is observed. 相似文献
17.
H. Alfvén 《Astrophysics and Space Science》1969,4(1):84-102
Detailed studies of the asteroidal belt are of importance for clarifying whether the asteroids are fragments of an exploded planet or represent an intermediate state in the accretion of planets.A study of the Hirayama family Flora shows that it contains three groups of bodies travelling in almost identical orbits, thus constituting three jet streams.It is shown that the formation of jet streams is difficult to reconcile with the exploded planet view.In order to decide whether the formation of jet streams is a general phenomenon in the asteroidal belt, it is necessary to determine the orbits of a large number of small asteroids. 相似文献
18.
The main result of this paper is the existence of a new family of central configurations in the Newtonian spatial seven-body
problem. This family is unusual in that it is a simplex stacked central configuration, i.e the bodies are arranged as concentric three and two dimensional simplexes.
相似文献
19.
The matrizants of simply and doubly symmetric orbits of the three-dimensional restricted problem of three bodies because of their symplectic character, can be transformed by means of multiplication with constant matrices into symmetric ones. As a result the bilinear relations between their elements, existing on account of the symplectic property, take linear and very simple forms. This fact is very useful in computer applications where these relations are used as criteria of accuracy. 相似文献
20.
A systematic and detailed discussion of planar periodic orbits, of a charged particle moving under the influence of an electromagnetic field of three celestial bodies, is given for the first time. In this problem the periodic orbits are all asymmetric. Numerical procedures are applied to find the families of these orbits and to study their stability. Moreover, the bifurcations of these families with families of three dimensional asymmetric periodic orbits are given. 相似文献