840 research outputs found
Determination of characteristics of newly discovered eclipsing binary 2MASS J18024395 +4003309 = VSX J180243.9+400331
During processing the observations of the intermediate polar 1RXS
J180340.0+401214, obtained 26.05.2012 at the 60-cm telescope of the Mt. Suhora
observatory (Krakow, Poland), variability of 2MASS J18024395+4003309 was
discovered. As this object was not listed in the "General Catalogue of Variable
Stars" or "Variable Stars Index", we registered it as VSX J180243.9+400331.
Additionally we used 189 separate observations from the Catalina Sky Survey
spread over 7 years. The periodogram analysis yields the period of
0d.3348837{\pm}0d.0000002.The object was classified as the Algol-type eclipsing
binary with a strong effect of ellipticity. The depths of the primary and
secondary minima are nearly identical, which corresponds to a brightness (and
maybe) mass ratio close to 1. The statistically optimal degree of the
trigonometric polynomial n=4. The most recent minimum occurred at HJD
2456074.4904. The brightness range from our data is 16.56-17.52 (V),
16.18-17.08 (R). The NAV ("New Algol Variable") algorithm was applied for
statistically optimal phenomenological modeling and determination of
corresponding parameters
Hyperbolic Chaos of Turing Patterns
We consider time evolution of Turing patterns in an extended system governed
by an equation of the Swift-Hohenberg type, where due to an external periodic
parameter modulation long-wave and short-wave patterns with length scales
related as 1:3 emerge in succession. We show theoretically and demonstrate
numerically that the spatial phases of the patterns, being observed
stroboscopically, are governed by an expanding circle map, so that the
corresponding chaos of Turing patterns is hyperbolic, associated with a strange
attractor of the Smale-Williams solenoid type. This chaos is shown to be robust
with respect to variations of parameters and boundary conditions.Comment: 4 pages, 4 figure
Program WWZ: Wavelet Analysis of Astronomical Signals With Irregularly Spaced Arguments
A program WWZ is introduced, which realizes the wavelet analysis using an
improved modification of the algorithm of the Morlet wavelet for a general case
of irregularly spaced data, which is typical for the databases available in
virtual observatories. Contrary to the well-known analogs, working with
regularly spaced (equidistant in time) arguments, we have implemented an
improved algorithm presented by Andronov, (1998KFNT...14..490A,
1999sss..conf...57A), which significantly increases the signal-to-noise ratio.
The program has been used to study semi-regular pulsating variable stars (U Del
et al.), but can be used for the analysis of signals of any nature.Comment: 5 pages, 2 figures, "Odessa Astronomical Publications", v. 26, No.1
(in press
Orbital stability of solutions to the problem on capillary-gravity waves in two-fluid layer
Going back to N. E. Kochin [1] problem about capillary-gravity waves on interface of
two-fluid flow is considered as bifurcation problem with spectral parameters
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