Possible observation sequences of Brans-Dicke wormholes

The purpose of this study is to investigate observational features of Brans-Dicke wormholes in a case if they exist in our Universe. The energy flux from accretion onto a Brans-Dicke wormhole and the so-called "maximum impact parameter" are studied (the last one might allow to observe light sources through a wormhole throat). The computed values were compared with the corresponding ones for GR-wormholes and Schwarzschild black holes. We shown that Brans-Dicke wormholes are quasi-Schwarzschild objects and should differ from GR wormholes by about one order of magnitude in the accretion energy flux.Comment: 5 pages, 6 figure

Self-force of a point charge in the space-time of a massive wormhole

We consider the self-potential and the self-force for an electrically charged particle at rest in the massive wormhole space-time. We develop general approach for the renormalization of electromagnetic field of such particle in the static space-times and apply it to the space-time of the wormhole with parameter of the mass, $m$. The self-force is found in manifest form; it is an attractive force. We discus the peculiarities due to massive parameter of the wormhole.Comment: 10 pages, 1 figure text correcte

Nearby low-mass triple system GJ795

We report the results of our optical speckle-interferometric observations of the nearby triple system GJ795 performed with the 6-m BTA telescope with diffraction-limited angular resolution. The three components of the system were optically resolved for the first time. Position measurements allowed us to determine the elements of the inner orbit of the triple system. We use the measured magnitude differences to estimate the absolute magnitudes and spectral types of the components of the triple: $M_{V}^{Aa}$=7.31$\pm$0.08, $M_{V}^{Ab}$=8.66$\pm$0.10, $M_{V}^{B}$=8.42$\pm$0.10, $Sp_{Aa}$ $\approx$K5, $Sp_{Ab}$ $\approx$K9, $Sp_{B}$ $\approx$K8. The total mass of the system is equal to $\Sigma\mathcal{M}_{AB}$=1.69$\pm0.27\mathcal{M}_{\odot}$. We show GJ795 to be a hierarchical triple system which satisfies the empirical stability criteria.Comment: 6 pages, 2 figures, published in Astrophysical Bulleti

A cyclic universe with colour fields

The topology of the universe is discussed in relation to the singularity problem. We explore the possibility that the initial state of the universe might have had a structure with 3-Klein bottle topology, which would lead to a model of a nonsingular oscillating (cyclic) universe with a well-defined boundary condition. The same topology is assumed to be intrinsic to the nature of the hypothetical primitive constituents of matter (usually called preons) giving rise to the observed variety of elementary particles. Some phenomenological implications of this approach are also discussed.Comment: 21 pages, 9 figures; v.4: final versio