Search Publications
Study of the Binary Star ADS 7251 by Observations on the 65-cm Refractor at Pulkovo from 1962-2018
Romanenko, L. G.; Izmailov, I. S.; Shakht, N. A. +1 more
Results are presented from a study of the binary star ADS 7251 (STF 1321) based on a uniform series of observations on the 65-cm refractor at Pulkovo from 1962 through 2018. The errors in the yearly average positions ρ and θ are equal to 0''.004 and 0°.02 for the photographic and 0."003 and 0.°01 for the CCD observations. A new orbit is calculated…
Galactic Kinematics Derived From Data in the RAVE5, UCAC4, PPMXL, and Gaia TGAS Catalogs
Bobylev, V. V.; Bajkova, A. T.; Tsvetkov, A. S. +1 more
The three-dimensional velocities of stars with high-precision positions, proper motions, and parallaxes from the Gaia TGAS catalog and radial velocities from the RAVE5 catalog are examined. A sample of 92395 stars with estimated ages yields the following kinematic parameters: (U, V, W)=(9.42, 20.34, 7.21)±(0.12, 0.10, 0.09) km/s, Ω = 26.29 ± 0.39 …
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…
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 …
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…
Physical parameters of the semiregular variable red giant 2 Cen
Arkharov, A. A.; Ruban, E. V.; Hagen-Thorn, E. I. +1 more
This is a study of photometric data from the Hipparcos catalog and spectrophotometric observations by a group of Pulkovo observers in Bolivia of the variable star 2 Cen (V806 Cen). Fourier analysis yields a more precise value of 12.57 d for the period of the brightness variation instead of 12.0 d. Light curves constructed from the photometric data…