2,448 research outputs found
Velocity Curve Analysis of the Spectroscopic Binary Stars V373 Cas, V2388 Oph, V401 Cyg, GM Dra, V523 Cas, AB And, and HD 141929 by Artificial Neural Networks
We used an Artificial Neural Network (ANN) to derive the orbital parameters
of spectroscopic binary stars. Using measured radial velocity data of seven
double-lined spectroscopic binary systems V373 Cas, V2388 Oph, V401 Cyg, GM
Dra, V523 Cas, AB And, and HD 141929, we found corresponding orbital and
spectroscopic elements. Our numerical results are in good agreement with those
obtained by others using more traditional methods.Comment: 13 pages, 8 figures, 14 Table
Application of a New Non-Linear Least Squares Velocity Curve Analysis Technique for Spectroscopic Binary Stars
Using measured radial velocity data of nine double lined spectroscopic binary
systems NSV 223, AB And, V2082 Cyg, HS Her, V918 Her, BV Dra, BW Dra, V2357
Oph, and YZ Cas, we find corresponding orbital and spectroscopic elements via
the method introduced by Karami & Mohebi (2007a) and Karami & Teimoorinia
(2007). Our numerical results are in good agreement with those obtained by
others using more traditional methods.Comment: 6 pages, 3 figures. Accepted for publication in Astrophysics & Space
Scienc
Ghost Chaplygin scalar field model of dark energy
We investigate the correspondence between the ghost and Chaplygin scalar
field dark energy models in the framework of Einstein gravity. We consider a
spatially non-flat FRW universe containing the interacting dark energy with
dark matter. We reconstruct the potential and the dynamics for the Chaplygin
scalar field model according to the evolutionary behavior of the ghost dark
energy which can describe the phantomic accelerated expansion of the universe.Comment: 11 pages, 5 figures, matched to published versio
Thermodynamical description of interacting entropy-corrected new agegraphic dark energy
To explain the accelerating universe driven by dark energy, a so-called
"entropy-corrected new agegraphic dark energy" (ECNADE), was recently proposed
with the help of quantum corrections to the entropy-area relation in the
framework of loop quantum cosmology. Using this definition, we study its
thermodynamical features including entropy and energy conservation. We discuss
the thermodynamical interpretation of the interaction between ECNADE and dark
matter in a non-flat universe bounded by the apparent horizon. We obtain a
relation between the interaction term of the dark components and thermal
fluctuation.Comment: 8 pages, version accepted for publication in Europhysics Letters
(2011
The effects of twisted magnetic field on coronal loops oscillations and dissipation
The standing MHD modes in a zero- cylindrical magnetic flux tube
modelled as a straight core surrounded by a magnetically twisted annulus, both
embedded in a straight ambient external field is considered. The dispersion
relation for the fast MHD waves is derived and solved numerically to obtain the
frequencies of both the kink (), and fluting () waves. Damping
rates due to both viscous and resistive dissipations in presence of the twisted
magnetic field is derived and solved numerically for both the kink and fluting
waves.Comment: 13 pages, 11 figure
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