Dynamical and kinematical near homoaxial rotations suitable for representation of nonuniformly rotating stars with extended atmospheres

In this paper, a nontrivial velocity tensor is suitably defined to represent in the common frame the so-called classes of dynamical and kinematical near homoaxial rotations of a deformable finite material continuum. These classes have simple and interesting physical interpretation, especially for treating of nonuniform rotation and its applications to astrophysics. Some important subclasses and derived classes (in the sense of related superclasses) are also discussed.Two coordinate systems are further introduced, one of which rotates uniformly while the other rotates nonuniformly, the latter defined by means of a generalized orthogonal coordinate transformation. Suitable conditions are then given, asserting that the above systems are preferred in the sense of preserving the motion of the continuum in its inertial class.Finally, the required concepts of homotropy and distributivity are defined and the method, by which the established mathematical framework will be subsequently used in applications, is discussed.     

Does Einstein's relationE=mc 2arise from the metric?

In this Letter we propose to consider the four-energy-space whose coordinates are composed as follows: (i) the coordinate ⁰ refers to the internal energy of the body (it is involved as an unknown function of the rest-energy and the kinetic energy of the body), and (ii) the coordinates ¹, ², ³ relate to the presence of gravitational, electromagnetic, and thermal energy at the location of the body respectively. We involve yet the proper energy interval d² by analogy to the four-interval ds ² in general relativity. From such metric field we calculate the Ricci tensor in the simplest case. In addition, we require its form to be the same one as that considered by Schwarzschild. Comparing both solutions we obtain Einstein's relationE=mc ².     

The third integral and the Hamiltonian

It is reiterated that any suggestion of the existence of a third integral is at variance with Poincaré's theorem on the non-existence of such integrals. Even in a purely numerical approach no form of a new integral can be constructed that is valid in every domain of the phase space; and it is devoid of meaning to use as a third integral different forms of functions in various cases.     

Galaxy-formation in pancake-models

Three concepts, statistically fair samples, high spatial resolution of pancakes and dynamical thresholding of density are used to define a procedure of extracting the large-scale distribution of luminous matter from pancake-models.Paper presented at the 11 th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

On the stability of strongly non-homogeneous self-gravitating equilibria

The stability analysis of several stronglynon-homogeneous, self-gravitating, one-dimensionalunstable equilibrium systems is carried out with the help of numerical techniques. The evolution of the perturbed unstable equilibria is studied by following the motion of the boundary curves of water bag configurations defining the systems.It is found that initial perturbations drive the unstable equilibrium states out of equilibrium at rates depending on the typical scale length of the perturbations : the instability rates increase with .     

Interstellar clouds and the formation of stars

Part I gives a survey of the drastic revision of cosmic plasma physics which is precipitated by the exploration of the magnetosphere throughin situ measurements. The pseudo-plasma formalism, which until now has almost completely dominated theoretical astrophysics, must be replaced by an experimentally based approach involving the introduction of a number of neglected plasma phenomena, such as electric double layers, critical velocity, and pinch effect. The general belief that star light is the main ionizer is shown to be doubtful; hydromagnetic conversion of gravitational and kinetic energy may often be much more important.In Part II the revised plasma physics is applied to dark clouds and star formation. Magnetic fields do not necessarily counteract the contraction of a cloud; they may just as well pinch the cloud. Magnetic compression may be the main mechanism for forming interstellar clouds and keeping them together.Part III treats the formation of stars in a dusty cosmic plasma cloud. Star formation is due to an instability, but it is very unlikely that it has anything to do with the Jeans instability. A reasonable mechanism is that the sedimentation of dust (including solid bodies of different size) is triggering off a gravitationally assisted accretion. A stellesimal accretion analogous to the planetesimal accretion leads to the formation of a star surrounded by a very low density hollow in the cloud. Matter falling in from the cloud towards the star is the raw material for the formation of planets and satellites.The study of the evolution of a dark cloud leads to a scenario of planet formation which is reconcilable with the results obtained from studies based on solar system data. This means that the new approach to cosmical plasma physics discussed in Part I logically leads to a consistent picture of the evolution of dark clouds and the formation of solar systems.     

Calculations of proximity effects in close binary systems

The proximity effects in the light curves of close binary systems are investigated with the aid of facilities provided by a high-speed, digital computer. The treatment follows, to a large extent, that summarized by Kopal (1959) and makes extensive use of the alpha-functions and related integrals provided by that author. The ellipticity and reflection effects are studied individually and different expressions are checked and compared. Test data are drawn continually from the well known system SZ Cam for which a rectified (in a more realistic sense) light curve is ultimately produced.     

Interplanetary dust particles and solar wind

An effect of the solar wind on the motion of interplanetary dust particles is investigated. An equation of motion is derived. It is pointed out that the Pseudo-Poynting-Robertson effect (and its special case — a corpuscular drag) and the corpuscular sputtering represent in reality one and the same effect within the framework of special relativity. In this context perturbation equations of celestial mechanics are also discussed.     

The loss-cone driven instability for Langmuir waves in an unmagnetized plasma

Analytic and numerical results are presented for the growth rate of Langmuir waves due to a loss-cone distribution of energetic electrons. The effect of the magnetic field on the wave-particle interaction is ignored, and the resonance condition is described in terms of a resonance hyperboloid in momentum space. The collisional evolution of a distribution of magnetically trapped electrons is followed numerically to show how a gap distribution develops. The growth is most favorable for an intermediate sized loss cone ( 45 °) and a gap distribution in which the mean energy of the suprathermal electrons is much larger than the thermal energy of the background electrons. It is plausible that loss-cone gap distributions do develop in the solar corona, and that they should lead to second harmonic plasma emission weakly polarized in the x-mode.     

A UV spectral atlas of a prominence

The ultraviolet spectrum of a large prominence has been observed with the High Resolution Telescope and Spectrograph (HRTS) on SPACELAB 2, 5 August, 1985. The spectrum covers the wavelength range 1335–1670 Å and shows numerous emission lines from gas at chromospheric and transition region temperatures. An Atlas of the prominence spectrum has been made showing absolute calibrated intensities on an accurate wavelength scale. The Atlas includes for comparison the corresponding UV-spectrum from an average quiet solar region.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

On the ratio between the mechanical fluxes in- and outside the solar chromospheric mottles

Available information about the relative areas on the quiet and active parts of the sun covered with magnetic elements, together with theoretical results on the relation between the photospheric mechanical flux and the consequent coronal electron density, allows one to conclude that the mechanical flux generated in the photospheric magnetic elements is about seven times as large as the flux generated in non-magnetic regions.     

Development of a real-time algorithm for detection of solar wind discontinuities

A study is presented of an algorithm, based on the statistical analysis of interplanetary magnetic field data, for the real-time detection of discontinuities in the solar wind. The analysis is based on the application of a sliding or searching algorithm together with a minimum variance treatment. A demonstration is given for a Pioneer data set from 29 August, 1966. This particular data set was chosen because it has been extensively studied (in terms of the fast forward MHD shock wave) by previous groups who utilized the three-dimensional Rankine-Hugoniot shock equations after identifying the shock on a subjective basis. Our procedure differs in that it is perfectly objective because of its searching technique. For this particular data set we identify the original shock with excellent agreement with the earlier studies of its normal vector, as well as an additional shock and tangential discontinuity, neither of which had been identified previously.     

Grains accretion processes in a protoplanetary nebula: Effects of the presence of liquid drops

The temporal behaviour of the mass distribution function of iron solid and/or liquid grains is studied in the inner regions of the solar nebula during its gravitational collapse. At distances from the centre of the nebula equal to 0.2 AU, 0.5 AU and 0.7 AU a mass limit for the accretionary process equal, respectively, to 17.6 g, 5.2 g and 3×10^–3 g is obtained in a reasonable time interval. The importance of a drop phase during the growth of the particles and of the sedimentation of the grains during the disk phase is underlined.     

Ускорение релятивистских электронов в плазменных реакторах и нелинейные спектры космических радиоисточников

( , 1977; , 1977). , , , . .     

The asymptotic limit of the form-factors α and β product for celestial bodies

The applicability of the properties of central configurations proceeding from the many-body problem to study of gaseous sphere cloud evolution during its gravitational contraction is justified. It is shown that the product runs to a constant value in the asymptotic time limit of simultaneous collision of all the particles of the cloud where is a form-factor of the potential energy and is a form-factor of the moment of inertia.The spherical bodies as well as ellipsoids of rotation and general ellipsoids with a one-dimensional mass distribution (k),k[0, 1] are found to possess the property =const.

---

. , - , , ., , - =const., , (k),k[0, 1].

     

Ovoid structures in the solar system: The coronae of Venus and Miranda,and the domes on the Earth

A comparison of Venus and Miranda coronae, and the Earth ovoidal structures, suggests that Venusian coronae, thermal structures associated with important compressional stress fields, could be compared to Archaean gneiss domes. Among Miranda coronae, Inverness has some characteristics not explained by either the raiser or the sinker models, and which deserve further investigation.     

Some studies on Hα-flares and microwave bursts in relation to sunspot magnetic configurations

Sunspot associated H-flares and microwave bursts occurring during the period 1972 to 1974 have been examined in relation to the magnetic strength and configurations of the sunspots and sunspot groups (abbreviated as spots). Important results obtained are: (i) percentage occurrences of flares exceeds those of microwave bursts up to a magnetic field strength of 2000 G while the reverse is true for higher field strength of spots, (ii) flare productivity (average number of flares per spot) and also burst productivity are comparatively higher in the case of and types of spots than in the case of other types of spots, (iii) the above productivities are predominantly high when magnetic configuration of spots changes during their life time, and (iv) impulsive type of microwave bursts are more associated with spots having changing type of magnetic configuration.     

The development and production of new,non-standard methods of observations with the radio telescope RATAN-600

The recent modernization of the RATAN-600 radio telescope at the Special Astrophysical Observatory has provided an opportunity to develop new procedures, called relay and zoned relay, for utilizing the new cone-surface secondary reflector. The geometric area, the horizontal beamwidth spatial resolution, and the permissible radiometer bandwidth are discussed. We are also able to estimate the changes in the sensitivities of the radio telescope-radiometer systems. The new procedures, called relay and zoned relay, allow us to obtain two-dimensional images of radio objects and to track the development of rapidly varying sources in any azimuth.Presented at the CESRA-Workshop on Coronal Magnetic Energy Release at Caputh near Potsdam in May 1994.     

Solar flare nomenclature

The evolution of solar flare nomenclature is reviewed in the context of the paradigm shift, in progress, from flares to coronal mass ejections (CMEs) in solar-terrestrial physics. Emphasis is placed on: the distinction between eruptive (Class II) flares and confined (Class I) flares; and the underlying similarity of eruptive flares inside (two-ribbon flares) and outside (flare-like brightenings accompanying disappearing filaments) of active regions. A list of research questions/problems raised, or brought into focus, by the new paradigm is suggested; in general, these questions bear on the interrelationships and associations of the two classes (or phases) of flares. Terms such as eruptive flare and eruption (defined to encompass both the CME and its associated eruptive flare) may be useful as nominal links between opposing viewpoints in the flares vs CMEs controversy.     

The existence of a ‘gap’ in the evolutionary sequence of pulsars

A replot of period derivative against period is done for about 300 pulsars, and the main features of the plot are discussed. The significance of a gap in this plot is reexamined and the existence of pulsars with nulling and subpulse drifting behaviour below this gap is pointed out. The implications of this for pulsar evolution are also discussed.