Dust particle in the solar gravitational and electromagnetic fields     

J. Klačka 《Earth, Moon, and Planets》1994,64(1):55-58

The action of the solar electromagnetic radiation (in the form of the Poynting-Robertson effect) on the motion of interplanetary dust particle in the gravitational field of the Sun is discussed from the theoretical point of view. Results are presented to all orders inv/c (c - speed of light,v -orbital velocity of the particle) - general relativistic formula is presented.  相似文献   

Poynting-Robertson effect: general case     

J. Klačka 《Earth, Moon, and Planets》1993,61(2):119-124

The effect of the solar radiation on the interplanetary dust particle is derived. The most simple correct derivation is presented (in terms of orderv/c) and each step is explained in detail. Derivation takes into account the general case of a spherical particle, not only perfectly absorbing one as in the case of Robertson's derivation (Robertson, 1937). Some new results on relativistic covariant formula are also presented.  相似文献   

On the stability of the zodiacal cloud     

J. Klačka 《Earth, Moon, and Planets》1994,64(1):95-98

The problem of the stability of the zodiacal cloud is scrutinized. The central idea of the paper sticks in the theoretical treatment of the action of the solar electromagnetic radiation on small interplanetary dust particles (IDPs). It is suggested that the virtual problem of the (in-)stability of the zodiacal cloud originated from the physically incorrect application of the Poynting-Robertson effect on IDPs. Real particles are not of spherical shape and so the braking acceleration is not proportional to -v/c. Depending on the shape (and other optical properties) of the particle, also spiralling outward from the Sun may occur.  相似文献   

Radiation forces on small particles in the solar system     

Joseph A. Burns  Philippe L. Lamy  Steven Soter 《Icarus》1979,40(1):1-48

We present a new and more accurate expression for the radiation pressure and Poynting-Robertson drag forces; it is more complete than previous ones, which considered only perfectly absorbing particles or artificial scattering laws. Using a simple heuristic derivation, the equation of motion for a particle of mass m and geometrical cross section A, moving with velocity v through a radiation field of energy flux density S, is found to be (to terms of order $\text{v}\text{c}$) , where ? is a unit vector in the direction of the incident radiation, $\text{r}\text{?}$ is the particle's radial velocity, and c is the speed of light; the radiation pressure efficiency factor Q_pr ≡ Q_abs + Q_sca(1 ? 〈cos α〉), where Q_abs and Q_sca are the efficiency factors for absorption and scattering, and 〈cos α〉 accounts for the asymmetry of the scattered radiation. This result is confirmed by a new formal derivation applying special relativistic transformations for the incoming and outgoing energy and momentum as seen in the particle and solar frames of reference. Q_pr is evaluated from Mie theory for small spherical particles with measured optical properties, irradiated by the actual solar spectrum. Of the eight materials studied, only for iron, magnetite , and graphite grains does the radiation pressure force exceed gravity and then just for sizes around 0.1 μm; very small particles are not easily blown out of the solar system nor are they rapidly dragged into the Sun by the Poynting-Robertson effect. The solar wind counterpart of the Poynting-Robertson drag may be effective, however, for these particles. The orbital consequences of these radiation forces-including ejection from the solar system by relatively small radiation pressures-and of the Poynting-Robertson drag are considered both for heliocentric and planetocentric orbiting particles. We discuss the coupling between the dynamics of particles and their sizes (which diminish due to sputtering and sublimation). A qualitative derivation is given for the differential Doppler effect, which occurs because the light received by an orbiting particle is slightly red-shifted by the solar rotation velocity when coming from the eastern hemisphere of the Sun but blue-shifted when from the western hemisphere; the ratio of this force to the Poynting-Robertson force is $\text{(}\text{R}{}_{\mathrm{\odot }}\text{r}\text{)}{}^2\text{[(}\text{w}{}_{\mathrm{\odot }}\text{n}\text{) ? 1]}$, where R_⊙ and w_⊙ are the solar radius and spin rate, and n is the particle's mean motion. The Yarkovsky effect, caused by the asymmetry in the reradiated thermal emission of a rotating body, is also developed relying on new physical arguments. Throughout the paper, representative calculations use the physical and orbital properties of interplanetary dust, as known from various recent measurements.  相似文献   

On the isotropization of electrons in synchrotron sources     

Donald B. Melrose 《Astrophysics and Space Science》1970,6(2):321-337

Electrons radiating synchrotron radiation develop a pitch angle anisotropy, and so become unstable to the coherent emission of hydromagnetic waves. The evolution of the coupled system of anisotropic electrons and waves is studied in the absence of any dissipation of the waves in the ambient medium. The anisotropy of the electrons approaches a steady state in which the anisotropy is energy independent and of orderv _A/c (v _A=Alfvén speed). The conditions for this small degree of anisotropy to be maintained are examined.Due to this scattering the bend in the synchrotron spectrum, from an inverse power law with index to one with index 4/3+1, due to an initial or recurrent injection of electrons, could only occur at infrared or higher frequencies.  相似文献   

The theory of relativity and super-luminal speeds     

Cao Shenglin 《Astrophysics and Space Science》1992,190(2):303-315

According to the different properties between the ds ² and the ds ⁴, it is discussed that the space-time will have the catastrophe nature on the Finsler metric ds ⁴ (see Cao, 1990, Paper II). The space-time transformations and the physical quantities will suddenly change at the catastrophe theory of the space-time. It will be supposed that only the dual velocity of the super-luminal-speed could be observed (see Cao, 1988). If so, a particle with the super-luminal-speedv>c, could be regarded as its anti-particle with the dual velocityv ₁=c ²/v<c.The project was supported by National Natural Science Foundation of China.  相似文献   

The comoving-frame equation of radiative transfer in relativistic flows     

Kazuhiko Morita  Noboru Kaneko 《Astrophysics and Space Science》1986,121(1):105-125

The comoving-frame equations of radiative transfer and moment equations to accurate terms of all orders inv/c are derived in the modified Lagrangian form. The equations exactly describe the interaction of radiation with matter in a relativistically moving medium in flat or curved spacetime. Two specialized sets of equations are presented: (1) the equation of radiative transfer and moment equations accurate to terms of second order (v ²/c ²), and (2) the transfer equation and moment equations for a radial flow in curved spacetime with the Schwarzschild-type metric.  相似文献   

Which electromagnetic equations apply in rotating coordinates?     

David L. Webster  Robert C. Whitten 《Astrophysics and Space Science》1973,24(2):323-333

It was discovered some years ago by Schiff that the equations divE = 4πQ and curlB - (1/c) ∂E/∂t = (4π/c)J for fields in vacuum do not carry over without change from an inertial frame to a frame with rotating axes of space coordinates, even for a region with all velocities of orderv≪c. However, the belief that all four of the field equations are invariant under such conditions is still prevalent and causes misconceptions in physical applications, including astrophysical and geophysical ones. The purpose of the present paper is therefore to call attention to Schiff's discovery, discussing its basis and its extension to fields in material media, and to interpret the additional terms that must be added to the equations in order to obtain valid transformations to rotating axes of coordinates.  相似文献   

The periastron advance in the second post-Newtonian approximation in general relativity     

G. Antonacopoulos  E. Tsoupakis 《Astrophysics and Space Science》1979,62(1):185-188

In this paper we present a second order post-Newtonian approximation to the Hamiltonian of theN-body system. Subsequently we improve the well-known Robertson's formula for the perihelion advancement by a correction term of orderc, wherec ^–4 is the velocity of light.  相似文献   

On the importance of the Poynting-Robertson effect on meteoroids     

E. M. Pittich  J. Klačka 《Earth, Moon, and Planets》1996,72(1-3):333-338

A small generalization of the equation of motion for the Poynting-Robertson effect is tested in order to find the significance of new terms. The test is made for dust particles ejected at perihelia of the orbit of the comet Encke. The particles are released at the speed of 40 m s^?1. Gravitational perturbations of planets, Poynting-Robertson effect and solar corpuscular radiation (solar wind) are considered. Other nongravitational effects may be represented by new terms in the suggested form of the nongravitational force. Various values of normal and transversal components of the perturbing nongravitational force are used. The final results of numerical integrations are compared with those obtained on the basis of the Poynting-Robertson effect.  相似文献   

On the importance of the Poynting-Robertson effect on meteoroids     

E. M. Pittich  J. Kla?ka 《Earth, Moon, and Planets》1995,71(3):333-338

A small generalization of the equation of motion for the Poynting-Robertson effect is tested in order to find the significance of new terms. The test is made for dust particles ejected at perihelia of the orbit of the comet Encke. The particles are released at the speed of 40 m s^–1. Gravitational perturbations of planets, Poynting-Robertson effect and solar corpuscular radiation (solar wind) are considered. Other nongravitational effects may be represented by new terms in the suggested form of the nongravitational force. Various values of normal and transversal components of the perturbing nongravitational force are used. The final results of numerical integrations are compared with those obtained on the basis of the Poynting-Robertson effect.  相似文献   

A restricted problem: Families of vertical critical periodic orbits (part II)     

K. Katopodis 《Astrophysics and Space Science》1986,125(1):149-155

In this paper we extend the computation of four families of vertical critical periodic orbitsb _1v ,b _2v ,c _1v ,c _2v , found in part I (Ichtiaroglouet al., 1980), for >0.5. The planar stability of the periodic orbits is also examined.  相似文献   

Solar wind and spin of small interplanetary particles     

Jozef Klačka 《Earth, Moon, and Planets》1994,66(2):213-216

The action of the solar corpuscular radiation on the rotational properties of small interplanetary dust particles is investigated. It is shown that the solar wind increases the angular momentum (spin) of the particle. Analytic solutions are presented for dominant terms in which quantities of the orders (v/u) ⁿ ,n 1, are neglected (v is the orbital velocity of dust particle around the Sun andu is the speed of the solar wind particles).  相似文献   

The comoving-frame equation of radiative transfer in a curvilinear coordinate system     

Naboru Kaneko  Kazuhiko Morita  Makoto Maekawa 《Astrophysics and Space Science》1984,107(2):333-346

The comoving-frame equation of radiative transfer and moment equations are derived in orthogonal, curvilinear coordinates, inclusive of terms of orderv/c. The equation of radiative transfer, which contains the terms due to the effect of curvature of coordinate lines explicitly as well as those of Doppler shift and aberration, is the generalization of Castor's equation for spherical symmetry and of Buchler's equation for Cartesian coordinates. The moment equations agree with Buchler's.  相似文献   

Radial Evolution of Well-Observed Slow CMEs in the Distance Range 2 – 30 <Emphasis Type="Italic">R</Emphasis><Subscript>⊙</Subscript>     

A. Shanmugaraju  Y.-J. Moon  Bojan Vrsnak  Dijana Vrbanec 《Solar physics》2009,257(2):351-361

We performed a detailed analysis of 27 slow coronal mass ejections (CMEs) whose heights were measured in at least 30 coronagraphic images and were characterized by a high quality index (≥4). Our primary aim was to study the radial evolution of these CMEs and their properties in the range 2 – 30 solar radii. The instantaneous speeds of CMEs were calculated by using successive height – time data pairs. The obtained speed – distance profiles [v(R)] are fitted by a power law v = a(R−b) ^c . The power-law indices are found to be in the ranges a=30 – 386, b=1.95 – 3.92, and c=0.03 – 0.79. The power-law exponent c is found to be larger for slower and narrower CMEs. With the exception of two events that had approximately constant velocity, all events were accelerating. The majority of accelerating events shows a v(R) profile very similar to the solar-wind profile deduced by Sheeley et al. (Astrophys. J. 484, 472, 1997). This indicates that the dynamics of most slow CMEs are dominated by the solar wind drag.  相似文献   

Rapidly rotating polytropes in the post-Newtonian approximation to general relativity     

G. G. Fahlman  S. P. S. Anand 《Astrophysics and Space Science》1971,12(1):58-82

The study of uniformly polytropes with axial symmetry is extended to include all rotational terms of order ⁴, where is the angular velocity, consistently within the first post-Newtonian approximation to general relativity. The equilibrium structure is determined by treating the effects of rotation and post-Newtonian gravitation as independent perturbations on the classical polytropic structure. The perturbation effects are characterized by a rotation parameter = ²/2G _c and a relativity parameter, =p _c / _c C ² , wherep _c and _c are the central pressure and density respectively. The solution to the structural problem is obtained by following Chandrasekhar's series expansion technique and is complete to the post-Newtonian rotation terms of order ². The critical rotation parameterv _c , which characterizes the configuration with maximum uniform rotation, is accurately evaluated as a function of . Numerical values for all the structural parameters needed to determine the equilibrium configurations are presented for polytropes with indicesn=1, 1.5, 2, 2 5, 3, and 3.5.  相似文献   

Poynting-Robertson effect I. Equation of motion     

J. Klačka 《Earth, Moon, and Planets》1992,59(1):41-59

Derivations of the Poynting-Robertson effect are presented. They are based on the corpuscular nature of light (unlike Robertson's 1937 derivation). It is justified why currently presented derivations are incorrect and why classical (nonrelativistic) physics is not able to understand this effect. Relativistically covariant derivations not only for perfectly absorbing (spherical) dust particles are presented. Fundamental feature of the interaction between the dust particle and the electromagnetic radiation is the conservation of the (proper) mass of the particle.I dedicate this article to the memory of my sister Zuzka Klaková (*5.7.1966 27.3.1991).  相似文献   

Effect of radiation on the stability of equilibrium points in the binary stellar systems: RW-Monocerotis,Krüger 60     

M. K. Das  Pankaj Narang  S. Mahajan  M. Yuasa 《Astrophysics and Space Science》2008,314(4):261-274

We have studied the stability of location of various equilibrium points of a passive micron size particle in the field of radiating binary stellar system within the framework of circular restricted three body problem. Influence of radial radiation pressure and Poynting-Robertson drag (PR-drag) on the equilibrium points and their stability in the binary stellar systems RW-Monocerotis and Krüger-60 has been studied. It is shown that both collinear and off axis equilibrium points are linearly unstable for increasing value of β ₁ (ratio of radiation to gravitational force of the massive component) in presence of PR-drag for the binary systems. Further we find that out of plane equilibrium points (L _i , i=6,7) may exists for range of values of β ₁>1 for these binary systems in the presence of PR-drag. Our linear stability analysis shows that the motion near the equilibrium points L _6,7 of the binary systems is unstable both in the absence and presence of PR-drag.  相似文献   

Linear size distribution of double radio sources in the constant speed symmetric expansion model     

D. G. Banhatti 《Astrophysics and Space Science》1988,140(2):291-300

The distribution of projected linear sizes of double radio sources is derived in an intrinsically-symmetric model in which the hotspots move away from the parent object at speedv before fading at timeT after their simultaneous origin. This is applied to a sample of doubles, separating the two asymmetry types closer-hotspot-brighter (yes-type) and closer-hotspot-fainter (no-type). Along with the arm-ratio distributions for the two classes, no-doubles very roughly indicatev0.3c, but no consistent value can be found for yes-doubles. A possible generalization of the model is suggested to allow different expansion speeds for different sources (though still retaining the intrinsic bilateral symmetry). Other effects that could be included in the model are also indicated.  相似文献   

On the aberration of waves in classical spacetime     

H. Günther 《Astronomische Nachrichten》2001,322(3):153-160

Recently Liebscher & Brosche (1998) proposed a new procedure to derive astronomical aberration for electromagnetic waves in the linear v/c limit using a non‐conventional definition of simultaneity for classical spacetime. The question of conventional and non‐conventional simultaneity will be analysed in this context.  相似文献