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Barkin Y.V.,Sternberg Astronomical Institute
Cosmic Research

This is the first part of a study to develop a modern theory of physical libration of the Moon caused by a liquid core. We use a special approach to studying Moon’s rotation relying on Poincaré’s planetary model and special forms of equations of motion in Andoyer and Poincaré variables. We construct expansions of the force function of the problem (the second harmonic of the selenopotential) in Andoyer and Poincaré variables for a high-precision description of disturbed orbital motion of the Moon. We investigate the main regularities in lunar rotational motion taken as a body with a solid nonspherical mantle and an ellipsoidal liquid core. The motion of the ideal liquid of the core is simple according to Poincaré. The Cassini laws can be dinamically interpreted for the motion of a synchronous satellite with a liquid core. The Cassini angle (the inclination of the rotation axis relative to the normal to the ecliptic plane) determined by us is very consistent with its determinations from laser observations. © 2016, Pleiades Publishing, Ltd. Source

Baturin V.A.,Sternberg Astronomical Institute
Astrophysics and Space Science

State-of-the-art perspectives of the equation of state (EOS) are considered in view of applications to stellar and solar modeling. While the present-day OPAL EOS is the best-known version of EOS, here we discuss the SAHA-S EOS as an alternative. We assume that the accuracy of the EOS is determined by an adequate description of the ionization of a number of chemical components. To get an adequate description of the ionization, one needs an extensive amount of ion levels, an appropriately truncated partition function, such as the Planck-Larkin function, and a high-level approximation to the Coulomb correction. The current version of the SAHA-S EOS includes an extended set of elements. It provides an accurate profile of the adiabatic exponent in the solar convection zone, which is then compared to a result of a helioseismic inversion. © 2009 Springer Science+Business Media B.V. Source

Sil'chenko O.,Sternberg Astronomical Institute
AIP Conference Proceedings

If bars are transient structures then nuclear star-forming rings, which are related to inner Lindblad resonances, are transient too. When star formation consumes all their gas fuel, they must leave low-contrast ring zones of relatively young stars. In early-type galaxies, these relic rings must be embedded into the large bulges and can be found only by mapping mean stellar population ages in the central parts of galaxies. Here I present a few examples of relic rings which were discovered by our team in the course of 2D spectroscopic surveys of nearby early-type disk galaxies. © 2010 American Institute of Physics. Source

Skugoreva M.A.,Peoples Friendship University of Russia | Sushkov S.V.,Kazan Federal University | Toporensky A.V.,Sternberg Astronomical Institute
Physical Review D - Particles, Fields, Gravitation and Cosmology

We consider cosmological dynamics in the theory of gravity with the scalar field possessing a nonminimal kinetic coupling to gravity, κG μνφμφν, and the power-law potential V(φ)=V0φN. Using the dynamical system method, we analyze all possible asymptotical regimes of the model under investigation and show that for sloping potentials with 02. Using a numerical analysis, we also construct exact cosmological solutions and find initial conditions leading to the initial kinetic coupling inflation followed either by a "graceful" oscillatory exit or by the secondary inflation. © 2013 American Physical Society. Source

Pshirkov M.S.,RAS Institute of Radio Engineering and Electronics | Postnov K.A.,Sternberg Astronomical Institute
Astrophysics and Space Science

We discuss a possible generation of radio bursts preceding final stages of binary neutron star mergings which can be accompanied by short gamma-ray bursts. Detection of such bursts appear to be advantageous in the low-frequency radio band due to a time delay of ten to several hundred seconds required for radio signal to propagate in the ionized intergalactic medium. This delay makes it possible to use short gamma-ray burst alerts to promptly monitor specific regions on the sky by low-frequency radio facilities, especially by LOFAR. To estimate the strength of the radio signal, we assume a power-law dependence of the radio luminosity on the total energy release in a magnetically dominated outflow, as found in millisecond pulsars. Based on the planned LOFAR sensitivity at 120 MHz, we estimate that the LOFAR detection rate of such radio transients could be about several events per month from redshifts up to z~1.3 in the most optimistic scenario. The LOFAR ability to detect such events would crucially depend on exact efficiency of low-frequency radio emission mechanism. © 2010 Springer Science+Business Media B.V. Source

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