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Statistical parallaxes and kinematical parameters of classical Cepheids and young star clusters
Dambis, A. K.; Rastorguev, A. S.; Glushkova, E. V. +1 more
The statistical-parallax method is applied for the first time to space velocities of 270 classical Cepheids with proper motions adopted from HIPPARCOS (1997) and TRC (Hog et al. 1998) catalogs and distances based on the period-luminosity relation by Berdnikov et al. (1996). The distance scale of short-period Cepheids (with periods less than 9 days…
Atmospheric chemical composition of the "twin" components of equal mass in the CP SB2 system 66 Eri
Bikmaev, I. F.; Yushchenko, A. V.; Musaev, F. A. +2 more
We determine the atmospheric chemical composition of the components of the CP SB2 system 66 Eri with approximately equal masses (M_A / M_B = 0.97) by using two CCD echelle spectra of the star. These spectra have been taken with the 1-m telescope at Special Astrophysical Observatory with a spectral resolution of 36 000 and a signal-to-noise ratio n…
The visual orbit of HD 98800
Tokovinin, A. A.
A family of possible visual orbits is computed for HD 98800AB, a young quadruple system of red dwarfs with a dusty disk. Published visual measurements, the radial-velocity difference, and an estimate of the sum of the component masses are used. Orbits with eccentricities from 0.3 to 0.6 and periods from 300 to 430 years result in dynamical paralla…
Space-age distribution of young open clusters and observational selection
Dambis, A. K.
Based on published photoelectric and CCD photometry and using the empirical ZAMS of Kholopov (1980) and the evolutionary-deviation curves obtained from the grid of isochrones computed by Maeder and Meynet (1991), we determine the distances, color excesses, and ages for 203 Galactic open clusters with log t < 8.2. The validity of the derived dis…
Parameters of four multiple systems from speckle interferometry
Hofmann, K. -H.; Tokovinin, A. A.; Balega, Yu. Yu. +2 more
New or refined visual orbital elements are presented for four double stars (HR 266 AP, 88 Tau AP = CHARA 18, eta Ori AB = McA18, ADS 16904 AP = CHARA 149) that are members of multiple systems. Relative photometry and positional speckle measurements with the 6-m telescope and published radial-velocity data for the stars are used. Photometric data a…
The density-wave nature of the Cygnus-Orion arm
Sitnik, T. G.; Mel'Nik, A. M.
Radial velocities and Hipparcos proper motions are used to construct the residual space velocity field for the OB associations in the Cygnus-Orion arm. We detected systematic motions typical of density-wave arms in Cyg OB1, OB3, OB7, OB8, OB9, Sco OB2, Cep OB2 and OB3 and those typical of the interarm space within the corotation radius in Per OB2,…
Chemically decoupled nucleus and the structure of the nuclear region in the spiral galaxy NGC 488
Sil'chenko, O. K.
The regular Sb-type galaxy NGC 488 was observed at the 6-meter telescope with the Multi-Pupil Field Spectrograph and found to have a chemically decoupled nucleus. Stellar population in the nucleus is twice richer in metals than that of the central bulge. An analysis of the isophotal shapes in the central part of the galaxy based on the images obta…