Search Publications
Absolute Calibration of the PL-Relations for the Classical Cepheids Based on the HIPPARCOS Parallaxes and the Distances of the Magellanic Clouds
Abrahamyan, H. V.
The zero points of the period-luminosity relations for the classical cepheids are calibrated based on the HIPPARCOS parallaxes of these stars. The calibrations are used to determine the distance moduli of the LMC and SMC: DMLMC = 18m.569 ± 0m.117 and DMSMC = 19m.070 ± 0m.119, respec…
Classical Cepheids and the Distances of HST Program Galaxies
Abrahamyan, H. V.
The distances of HST program galaxies are revised using the PL-relations we have obtained previously along with a different method from that employed by Freedman et al. On the average, the resulting distances to these galaxies have higher internal accuracies than those obtained before by others. In addition, we have used no corrections for metalli…
On the Distance to Nearby Dwarf Galaxy NGC 1569
Karachentsev, I. D.; Makarova, L. N.
We present stellar photometry of two HST/WFPC2 fields situated at the far periphery of the poststarburst galaxy NGC 1569. Their F606W and F814W images have been taken from the HST data archive. Judging by the obtained color-magnitude diagrams, we suggest presence of the old disk population (old red giants) of NGC 1569, which extends as far as Fiel…
Kinematic Analysis of Near and Far Stars in the Hipparcos Catalog
Vityazev, V. V.; Drobit'ko, E. V.
The proper motions of stars in the main sequence and of luminosity class III giants are analyzed kinematically. A new method has been used for reliably separating all the parameters of the Ogorodnikov-Milne model based on representing the proper motions of the stars in coordinate systems whose poles lie on each of the three principal axes of the g…
Determination of Distances to Galaxies of the NGC 1023 Group. The Hubble Constant
Tikhonov, N. A.; Galazoutdinova, O. A.
On the basis of photographs from the 6 m Large Azimuthal Telescope and the Hubble Space Telescope, VRI photometry of stars in 11 galaxies in the NGC 1023 group has been carried out. The distances to these galaxies were determined by the method of brightest stars. The distances to NGC 925 and NGC 1023 were determined from the position of the top of…
Search for Star Groups in the Solar Neighborhood
Orlov, V. V.; Kazakevich, E. É.
Two methods are proposed for finding star groups in coordinate and velocity spaces, which were used to investigate stars of the Hipparcos Catalog with known radial velocities in the solar neighborhood with a radius of 125 pc. Thirteen probable nonrandom star groups in coordinate space and five moving groups in velocity space were found. These resu…
Classification of the light curves of Mira variables
Melikian, N. D.
Based on an analysis of light curves of 223 long-period variables of the Mira Ceti type, recorded using the HIPPARCOS space telescope, it is shown that all the light curves of these stars can be divided by outward form into two groups: stars exhibiting simple light curves of sinusoidal shape and stars with complicated light curves, with hump-shape…
On the expansion of stellar association Per OB2
Mirzoyan, L. V.; Hambaryan, V. V.; Akopian, A. A. +2 more
The analysis of the proper motions of bright members of the Per OB2 association on the basis of Hipparcos high-accuracy astromethc observations is presented. The existence of two different subgroups of OB-stars in the Per OB2 association that are in the state of expansion is considered. The expansion ages are calculated as 1.3 and 1.9×106
On Mass Loss from HD46300 - a Supergiant of Luminosity Class 1B
Oganesyan, D. B.
Using archival IUE data we give the results of an analysis of the profile of the Mg II k and h lines for HD46300, an AO1b-supergiant. Evidence of mass loss by the star was detected; its most probable nature is the ejection of matter in a cloud. Estimates are made for certain parameters of this cloud.