Alexey Mironov

Accuracy of stellar parameters determined from multicolor photometry

The development and application of new methods for intelligent analysis and extraction of information from digital sky surveys carried out in various spectral domains have now become a popular field in astrophysical research and, in particular, in stellar studies. Modern large-scale photometric surveys provide data for 105–106 relatively faint objects, and the lack of spectroscopic data can be compensated by the cross identification of the objects followed by an analysis of all catalogued photometric data. In this paper we investigate the possibility of determining the effective temperature, surface gravity, total extinction, and the total-to-selective extinction ratio based on the photometry provided in the 2MASS, SDSS, and GALEX surveys, and estimate the accuracy of the inferred parameters. We use a library of theoretical spectra to compute the magnitudes of stars in the photometric bands of the above surveys for various sets of input parameters. We compare the differences between the computed magnitudes with the errors of the corresponding surveys. We find that stellar parameters can be computed over a sizable domain of the parameter space. We estimate the accuracy of the resulting parameters. We show that the presence of far-ultraviolet data in the available set of observed magnitudes increases the accuracy of the inferred parameters.

The LYRA-B Space Experiment: Goals and Principles for Its Realization

We describe goals and principles for the realization the Lyra-B space experiment onboard the International Space Station, which is currently being prepared at the Sternberg Astronomical Institute. The main goal of the experiment is to carry out a high-accuracy, multicolor all-sky survey of stars down to 16m–17m. The detailed structure of the expected observational data, their possible scientific use, and a number of technical problems are discussed.

On the Astron UV Space Mission Data

Abstract The Soviet UV space mission Astron, launched in 1983, had been operational for eight years as the largest ultraviolet space telescope during its lifetime. Astron provided a lot of observational material for various types of astrophysical objects, but unfortunately these data were not widely available and, as a result, unduly forgotten. Here we present some results of our comparison of the Astron data to the modern UV stellar data, such as the NGSL spectral library, discuss the precision and accuracy achieved with Astron, and make some conclusions on potential application areas of these data.

The Possibility of a Deep Scanning Survey of Part of the Sky from a Low-Orbit Spacecraft with Fixed Orbital Orientation

Abstract We analyze the possibility of performing a deep survey of a part of the sky near the poles of the spacecraft orbit from a low-orbit spacecraft with fixed orbital orientation. The survey depth can be increased by several magnitudes by reducing the surveyed sky area to strips along one or two minor circles at constant declination. The surveyed area is scanned by precession of the spacecraft.

Observation of Luni-Solar Tides by the Long Base Laser Interferometer

Results of observations of tidal strains of the crust in the tectonically active region of the Northern Caucasus (the Elbrus mountain area) carried out with the use of the Baksan laser interferometer strainmeter over the period from 2003 through 2006 are presented. Harmonic analysis is performed with the help of the ETERNA software package. Statistically significant time variations in the amplitudes of the main tidal waves M2 and O1 are revealed. The influence of the Baksan canyon topography on tidal strains is estimated at 22% (an increase in the measured strain values). The reduced amplitude factors of the main diurnal O1 and semidiurnal M2 waves are underestimated. Numerical modeling of tidal anomalies produced by regional heterogeneous inclusions is performed in a 2–D approximation. The observed anomaly of the M2 wave (12%) is shown to be due to the influence of the main magmacontrolling fault associated with the deep magma source of the Elbrus dormant volcano.

Monitoring the State of the Magmatic Structures of Elbrus Volcano Based on Observation of Lithosphere Strains

An analysis of crustal strain recorded by the Baksan laser interferometer revealed a shallow magma chamber in the structure of Elbrus Volcano (The Northern Caucasus, Russia). The analysis is based on estimation of parameters of magmatic structures resonant modes excited by teleseismic signals. The resonance parameters we have found were interpreted in the framework of contemporary models of magma resonators. The depth and dimension of the magma chamber, as well as the properties of the magma fluid were estimated. It was suggested the changing the magma state due to rising the intrachamber pressure.

On a New Technique for Discovering Variable Stars

Abstract A technique for discovering variable stars based on the calculation of the correlation coefficients is proposed. Applications of the technique are shown on the results of numerical experiments and on the Hipparcos photometric data.