Search for contact systems among EB-type binaries

In a search of contact systems among EB-type binaries, the existing photometric observations of ES Lib and AR Boo have been analysed. We find that ES Lib is a semi-detached system, with the primary filling the Roche lobe. AR Boo is instead found to be a contact system, with no lobe overfilling, and with a large temperature difference between the components, but this solution has to be considered as temptative, because of the poor quality of the data and the lack of any spectroscopic information.Associated with the Istituto Nazionale Fisica Nucleare, Italy.     

Photometric Elements of the Eclipsing Binary AZ Vir

Using WOOD 's (1972) model we have analyzed MEINUNGER 's (1977) B and V photoelectric light curves – as yet unsolved–of the W UMa-type eclipsing binary AZ Vir, for which no photometric elements have as yet been determined. Our results describe AZ Vir as a contact pair in which the star eclipsed at the deeper minimum is smaller than its companion. AZ Vir appears to conform to the general properties of the W-type subclass of W UMa systems.     

Das Korrespondenzprinzip in der Kosmologie I. Der isotrope Kosmos als NEWTONscher Grenzfall der relativistischen Gravitationstheorien

According to the principle of correspondence (in HEISENBERG 's formulation) each general relativistic theory of gravitation must give a NEWTON ian representation for an isotropic cosmos with the ROBERTSON -WALKER metric. Indeed, the FRIEDMANN equations can be interpreted as the expression for the HAMILTON ian H of a closed NEWTON ian system of the cosmic fundamental particles, written in the rest-system of the center of gravity. In this HAMILTON ian H only the relative-coordinates and the relative-velocities of the particles are present and one can write H without absolute quantities but only with MILNE 's relative-quantities. The time-independence of the HAMILTON ian H = 0 is the FRIEDMANN equation. – This NEWTON ian deduction of the FRIEDMANN equation is more general than the relativistic deduction and than MILNE 's deduction for a NEWTON ian fluid, too. In the general NEWTON ian form H the parameter f M of the active mass can be an arbitrary function of the cosmic time t. The choice f = f(t), M = M(t) defines the divers modifications of relativistic cosmology. – In general relativity fM = const and M = const are resulting from EINSTEIN 's equations and from EINSTEIN 's principle of equivalence.     

The young open cluster Trumpler 3

We present a photometric and spectroscopic study of the poorly investigated open cluster Trumpler 3. Basic parameters such as the age of 70 ± 10 Myr, the color excess E (B – V) = 0.30 ± 0.02 mag, the distance of 0.69 ± 0.03 kpc and the limiting radius of 12′ were redetermined and compared with previous preliminary studies. The distance of 0.65 ± 0.09 kpc was determined independently by spectral parallaxes. Simultaneously, our analysis allowed us to estimate a total number of members to be N_tot = 570 ± 90 and a total mass of the cluster to be M_tot = 270 ± 40 M_⊙. We also determined a state of cluster's dynamical evolution. We conclude that Trumpler 3 is a young low‐massive stellar ensemble with a typical mass function slope, located near to the outer edge of the Galaxy's Orion Spur. As a result of a wide‐field search for short period variable stars, 24 variables were discovered in the cluster's area. Only one of them – a variable of the γ ‐Dor type – was found to be a likely cluster member (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Time series photometric spot modelling – V. Phase coherence of spots on UZ Librae

We present spot models for nine years of continuous VI_c photometry of UZ Lib from 1993–2001. The relatively stable double‐humped light curve shape suggests extreme phase coherence. From the spot‐modelling analysis, we found that the major spots or spot groups are always located on the hemisphere facing the secondary star and exactly in the opposite hemisphere anti‐facing the secondary. Several single‐humped light curves and our suggested binary scenario rule out a pure ellipsoidal variability as the cause of the double‐humped light curve shape. We try to explain this preferred spot pattern with a magnetic‐field structure that connects the two components, as suggested earlier for RS CVn stars in general. A possible 4.8 years spot cycle is found from the long‐term brightness variations but needs confirmation. We rediscuss the basic astrophysical data of UZ Lib. The Hipparcos parallax is likely wrong, a possible reason could be that UZ Lib is e.g., a triple system.     

A New Light Curve Analysis of the Eclipsing Binary SX Aur

Using WOOD 's (1972) model, we have analysed BONDARENKO 's (1974) two-colour photoelectric observations – till now unsolved – of the eclipsing binary SX Aur. Our photometric solutions turn out to be in substantial agreement with those derived by CHAMBLISS and LEUNG (1979); they confirm that SX Aur is a post-mass exchange (case A) semi-detached system.     

Eddingtons Zahlen,Einsteins Kriterium und Rydbergs rationelles Dimensionssystem

The discussions about the meaning of the “hierarchy of interactions” and in connection with this about the role of Eddington's “cosmological number” imply the question of the “big numbers” in physics. According to Einstein's and Bridgman's criteria such “big numbers” are hints at unsolved problems in the foundations of physics. Eddington gives a theory of the big number like cosmological quantities. – A new point of view on this question may be to remember Rydberg's suggestion on independigly physical dimensions of lengths L, surfaces S, and volumina V, and to remember Dällenbach's suggestion to introduce a new universal constant α which describes the operational connections between the quardrate of lengths L² and the surface S in microphysics. Coulomb's and Nwton's laws have the same structure. But, the electrical forces are depending on L^-2 and the gravitational forces are depending on S^-1 ∼ (1/α) L^-2 because “gravitation is geometry”. In Planck's elementary units h, c and f Dällenbach's “surface-constant of the vacuum” α is a pure number α ≈ hc/fm², th. i. Eddington's cosmological number ω ∼ 10⁴⁰. However, Rydberg's physical dimensions in geometry and Dällenbach's constant suggest new formulations of the question of “geometrization of physics” and “physicallization of geometry” and the connections between cosmology and microphysics.     

Photometric variability of four coronally active stars

We present photometric observations of four stars that are optical counterparts of soft X-ray/EUV sources, namely 1ES 0829+15.9, 1ES0920-13.6, 2RE J1 10159+223509 and 1ES 1737+61.2. We have discovered periodic variability in two of the stars, viz., MCC 527 (1ES 0829+15.9; Period = 0 ^d .828 ± 0.0047) and HD 81032 (1ES 0920-13.6; Period = ∼ 57.02 ± 0.560 days). HD 95559 (2RE J1 10159+223509) is found to show a period of 3 ^d . HD 160934 (1ES1737+61.2) also shows photometric variability but needs to be monitored further for finding its period. These stars most likely belong to the class of chromospherically active stars.     

Das Korrespondenzprinzip in der Kosmologie. II. Klassische und relativistische Darstellungen der Weltmodelle

According to the equivalence between the FRIEDMANN equation of relativistic cosmology and the condition for the time-independence H = o of the HAMILTON ian H of an isotropic particle-system in the NEWTON ian mechanics (which equivalence is proved in the part I of our paper) we construct the corresponding classical HAMILTON ians to the relativistic world-models. Each cosmological model which is resulting from a physically meaningful gravitation theory must give a FRIEDMANN equation as the cosmological formulation of the time-independence condition of the energy H for the corresponding NEWTON ian N-particle system. In general relativity, EINSTEIN's field equations are including EINSTEIN's strong principle of equivalence and are giving the constance f = o and M = o of the gravitation-number f and of the mass M of the universe additional to FRIEDMANN's equation. – In special relativity, we have fM = o and this MILNE -universe is possessing a NEWTON ian and a general relativistic interpretation, too. – However, if the postulate together with the “cosmological principle” other principles about the world structure, too (p. e. MACH'S or DIRAC'S principle or the “perfect cosmological principle” by the steady-state cosmology), then EINSTEIN'S weak principle of equivalence can be fulfilled, only. In these world models the gravity-mass fM becomes a function of the cosmic time t [d/dt(fM) ± o] and this variability of fM is compatible with the constance H = o of the energy H of the NEWTON ian particle-system. For flat three-dimensional cosmological spaces (with H = Ḣ = o) a creation of rest-mass (M > o) is possible. This creation is the pecularity of the steady-state cosmos (with M > o, f = o) and of JORDAN'S cosmos (with M > o, f < o). The MACH -EINSTEIN -doctrine about the perfect determination of the inertia and of the space-time-metric by the cosmic gravitation is founded on the substitution of the NEWTON ian HAMILTON ian by a GAUSS -RIEMANN ian gravitation potential U^*(r_AB' v_AB) (TREDER 1972). Therefore, the FRIEDMANN equation for a universe with MACH'S principle is resulting from the analytical expression of the time-independence of this RIEMANNian potential U* = 0. In the case of such MACH-EINSTEIN's-Universes EINSTEIN'S condition 3fM = c8r between the mass A4 and the radius Y of the universe is valid additional to FRIEDMANN'S equation. For these universes, the EINSTEIN condition determinates the instantaneous value of the gravitation-number f. - The explicite form of the conditions H = o or h' = o gives the equation of motion for the cosmic fundamental particles with attraction and repulsion forces, generally.     

Multi-Facility Study of the Algol-Type Binary δ Librae

Various branches of observational information, and related physical problems concerning the bright, relatively close, Algol binary δ Lib are discussed. Times of minimum light confirm the classical Algol status, which, combined with the optical and IR photometry of Lazaro et al. (2002), provide the basis for a good understanding of the system’s basic parameters. New spectroscopy from the Coudé spectrograph of the Rozhen Observatory (Bulgaria) allows further information on the model and the mass transfer process. Very high resolution radio observations would also have much to reveal about astrophysics of the semi-detached configuration, not only directly, by informing about the outermost envelopes of the components, but indirectly through high accuracy positional information. We show how this may be related to careful period and astrometric studies. δ Lib thus provides a rich source of information on the astrophysics of the Algol configuration.     

Photometrically determined mean surface magnetic fields of Ap stars

The photometrically determined mean surface magnetic fields B_S need a revision. None of the stars for which B_S can be measured directly by Zeeman line splitting fulfils the relation between the photometric parameter Δ(V₁ – G) and the mean surface field B_S, which is used by NORTH , CRAMER and MAEDER to determine B_S for other B2 – A3 stars. The ratio B_eff^Max/B_S for stars, which define North's relation, shows unreasonable large values.     

On resonant thermonuclear reaction rate integrals- closed-form evaluation and approximation considerations

The central problem in the theory of stellar nucleosynthesis (and in reaction theory of controlled thermonuclear fusion as well) is the determination of thermonuclear reaction rates. Continuing our preceding paper on closed-form evaluation of nonresonant reaction rate integral (HAUBOLD and JOHN 1978) now we consider a general thermonuclear reaction rate integral involving the full BREIT -WIGNER resonance cross section. Discerning between two cases – energy-independent partial widths and energy-dependent partial width – we evaluate the arising parameter-dependent integrals in closed form by means of MEIJER 's G-functions of one and two variables. At next, by using the BUNJAKOVSKIJ -SCHWARZ inequality we derive global upper bounds for thermonuclear reaction rate integrals with arbitrary admissible values of input parameters. Finally, in case of great values of the characteristic parameter COULOMB barrier energy divided by thermal energy we give an asymptotic representation of the general resonant reaction rate integral.     

Singularitäten in der Allgemeinen Relativitätstheorie

“Regular solutions of EINSTEIN 's equations” mean very different things. In the case of the empty-space equations, R_ik = 0, such solutions must be metrics g_ik(x^l) without additionaly singular “field sources” (EINSTEIN 's “Particle problem”). – However the “phenomenological matter” is defined by the EINSTEIN equations R_ik – 1/2g_ikR =–xT_ik itselves. Therefore if 10 regular functions g_ik(x^l) are given (which the inequalities of LORENTZ -signature fulfil) then these g_ik define 10 functions T_ik(x^l) without singularities. But, the matter-tensor T_ik must fulfil the two inequalities T ≥ 0, T ≥ 1/2 T only and therefore the EINSTEIN -equations with “phenomenological matter” mean the two inequalities R ≥ 0, R ≤ 0 which are incompatible with a permanently regular metric with LORENTZ -signature, generally.     

Observational background of TREDER'S gravitation theory in cosmology and the role of viscosity

Starting from solutions of TREDER'S field equations for a homogeneous and isotropic universe filled with incoherent matter (p = 0) relations between observation quantities are derived and discussed. The FRIEDMANN time is of the order of HUBBLE age, the deceleration parameter may principally possess any positive or negative value, hence it is also possible to explain any m,z-relation completely in the frame of this theory. A decision between EINSTEIN'S theory and TREDER'S by cosmological observations is impossible. – Considering a realistic medium which consists of particles and radiation, energy dissipation originating from bulk viscosity (due to the interaction of particles and quanta) prevents cosmological singularities. Thereby entropy, now present in form of relict radiation, is produced. This process generates large amounts of restmass-free energy in the phase of maximum contraction and therefore could as well explain the large luminosity of compact single objects (quasars?). Models with energy dissipation are not invariant with respect to time reflection t→ – t in contrast to EINSTEIN'S theory. If demanding the universe to be free from singularities the direction of cosmic time is uniquely determined. This demand then restricts the possible relations between observation data to the case q₀ = + 1 being in accord with the latest determination by SANDAGE .     

General Transformation Factor from Number of Stars of Tenth Visual Magnitude to Raleigh Per Angstrom Or Nano Lambert for Different Wavelengths

In the nearest neighbour method of the random distribution of N objectson a sphere surface the variable (N-1) sin²(α/2) isproposed to be used instead of the angular distance α. Thenboth the expected mean and variance equal to one for large N, and both theStudent's test and F-test are especially simple. An illustrative applicationshows that the superclusters – collected in the All-Sky Catalogues ofSuperclusters of Abell-ACO Clusters – need not be distributedrandomly.     

VR c photometry of dwarf cepheids (II)

In this paper, we derived the empirical relationship between stellar surface brightness parameter (F _v) and (V —R _c) colour in Cousins system appropriate to dwarf cepheids. Also theoretical counterpart to this relation has been calculated from model atmospheres. The theoretical relation is in reasonable agreement with the empirical relation but reveals small sensitivities to surface gravity and metallicity. Both relations were used to apply the surface brightness method to estimate the radius of four dwarf cepheids of YZ Boo, AD CMi, XX Cyg, and EH Lib which were observed withV andR band in Cousins photometric system by Kim and Joner (1994). We could obtain the reliable result for AD CMi and it was found that, for three other variables, there are large phase shifts between angular diameter variation and radial displacements.     

Swift observations of GW Lib: a unique insight into a rare outburst

The second known outburst of the WZ Sge type dwarf nova GW Lib was observed in 2007 April. We have obtained unique multiwavelength data of this outburst which lasted ∼26 days. The American Association of Variable Star Observers ( AAVSO ) recorded the outburst in the optical, which was also monitored by Wide Angle Search for Planets , with a peak V magnitude of ∼8. The outburst was followed in the ultraviolet and X-ray wavelengths by the Swift ultraviolet/optical and X-ray telescopes. The X-ray flux at optical maximum was found to be three orders of magnitude above the pre-outburst quiescent level, whereas X-rays are normally suppressed during dwarf nova outbursts. A distinct supersoft X-ray component was also detected at optical maximum, which probably arises from an optically thick boundary layer. Follow-up Swift observations taken 1 and 2 years after the outburst show that the post-outburst quiescent X-ray flux remains an order of magnitude higher than the pre-outburst flux. The long interoutburst time-scale of GW Lib with no observed normal outbursts support the idea that the inner disc in GW Lib is evacuated or the disc viscosity is very low.     

Possible third body effects in the period changes of four Algol binaries: RY Aqr,SZ Her,RV Lyr and V913 Oph

An investigation of the orbital period changes of the neglected eclipsing binaries, RY Aqr, SZ Her, RV Lyr and V913 Oph, is presented based on all published minima times. Although the explanation of magnetic activity on the surface of the secondaries of the studied Algols is still open, the preferred light‐time effect due to the unseen components around the systems seems more plausible in explaining the tilted sinusoidal variations with relatively high‐amplitudes. The minimal mass values of possible tertiary components have been estimated to be about 1.06, 0.25, 0.78 and 2.85 M_⊙ for RY Aqr, SZ Her, RV Lyr and V913 Oph, respectively and the results indicate that their contributions to the total light of the eclipsing pairs are measurable with high accuracy photometric and spectroscopic data, if they exist. Applegate's (1992) model has been discussed as an alternative mechanism assuming that the cooler components have magnetic cycles. It is found that the model parameters of RY Aqr and V913 Oph are consistent with the required values in Applegate's model. In addition to the first detailed orbital study on these systems, a statistical survey on the character of the O – C variations of classical Algols has revealed that about 50 percent of the systems show cyclic behavior. This means that the presence of possible third bodies around classical Algols should be tested with careful analysis using new data. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

On Soldner's Value of Newtonian Deflection of Light

It is shown that in Soldner's publication of 1801 the angle of deflection for light in the sun's gravitational field is given with the correct Newtonian value. A factor 2, which had been the occasion for misinterpretation, has to be attributed to the terminology used by German physicists and astronomers of that time – There are, however, two mistakes in Soldner's publication. As they do not affect his analysis they must be interpreted as mere misprints.