Search Publications
Stability valley for strange dwarfs
Vartanyan, Yu. L.; Hajyan, G. S.; Grigoryan, A. K. +1 more
This is a study of the stability of strange dwarfs, superdense stars with a small self-confining core (Mcore < 0.02 M⊙) containing strange quark matter and an extended crust consisting of atomic nuclei and degenerate electron gas. The mass and radius of these stars are of the same orders as those of ordinary white dwarfs. …
Effect of hot jupiters on the variability of stellar radiation
Arkharov, A. A.; Ruban, E. V.
The effect of hot jupiters on the variability of light from 14 bright stars with planets that are listed in the Pulkovo Spectrophotometric Catalog (PSC) and the Hipparcos photometric catalog is studied. The spectral range 320-1080 nm and the Vt and Bt photometric magnitudes are examined. The photometric observations reveal microvariability of the …
Young stars in gas-dust disks. I. Fomalhaut
Arkharov, A. A.; Ruban, E. V.
This is a single-factor analysis of the variance of the average quasimonochromatic magnitudes of Fomalhaut, α PsA, in the 325-1080 nm spectral range for different observation seasons collected in the Pulkovo Spectrophotometric Data Base (PSDB). The overall variance of the data combined over several seasons is decomposed into components characteriz…
Young stars in gas-dust disks. II. Vega (α Lyr) and β Pic
Arkharov, A. A.; Ruban, E. V.
Observational data for Vega, α Lyr in the 325-1080 nm range from various years are studied using material stored at the Pulkovo Spectrophotometric Data Base (PSDB). It is shown that the spectrophotometric temperature of the star was lower than the effective temperature according to data from all the observational seasons. Possible reasons for this…
Interacting galaxies in deep fields of the Hubble Space Telescope
Reshetnikov, V. P.; Mohamed, Y. H.
The morphologies of galaxies in several deep fields (HDF-N, HDF-S, HUDF, GOODS, GEMS) of the Hubble Space Telescope are analyzed visually. Lists are made of the galaxies with tidal structures (tails, bridges) and type M51 galaxies in these fields. Photometric characteristics and estimated redshifts for most of these objects are found in the publis…
Method for analyzing the spatial distribution of galaxies on gigaparsec scales. II. Application to a grid of the HUDF-FDF-COSMOS-HDF surveys
Nabokov, N. V.; Baryshev, Yu. V.
Using the deep fields of COSMOS, FDF, HUDF, and HDF-N as an example, we discuss the prospects for and limitations on the method for searching for superlarge structures in the spatial distribution of galaxies proposed in the preceding article of this series. An analysis of the distribution N(z) of photometric redshifts in a grid of the deep fields …
Microvariability and fast variability of stars. II. The semiregular red giants L2 Pup, 2 Cen, η Gem, and σ Lib
Arkharov, A. A.; Ruban, E. V.
This is a study of the photometric magnitudes Vt and Bt of four semiregular red giants of spectral classes M3-M6 III, L2 Pup, 2 Cen, η Gem, and σ Lib, from the Hipparcos catalog to search for microvariability and rapid variations in their emission. It is shown that low amplitude variability shows up in the form of rapid changes in the b…
Microvariability and fast variability of stars. I. standard stars
Arkharov, A. A.; Ruban, E. V.
This is a study of observations of the photometric quantities Vt and Bt, reported in the Hipparcos catalog, for 15 standard stars in order to search for microvariability and rapid variability in their emission. The microvariability is found to be characterized mainly by smooth fluctuations in the brightness. Changes in the magnitudes of the stars …
Quasiperiodic oscillations in the light curve of GRB 080319B
Dranevich, V. A.; Dmitriyev, P. B.; Gnedin, Yu. N.
A modified spectral analysis technique is used to study the temporal structure of the emission from the γ-ray burst GRB 080319B detected in three space missions, Swift/BAT, Wind/KONUS, and Integral/SPI ACS. The energy range of the γ rays detected in these experiments covers 15-10000 keV. The time resolution for the first two of these experiments w…
Determining the fundamental parameters of F and G supergiants
Lyubimkov, L. S.; Rachkovskaya, T. M.; Poklad, D. B.
A technique for determining the effective temperature Teff and the acceleration of gravity log g of F and G supergiants is discussed using four bright stars as examples, specifically two F supergiants, α Lep(F0 Ib) and π Sgr (F2 II), and two G supergiants, β Aqr (G0 Ib) and α Aqr (G2 Ib). In all four cases the parameter log g was derive…