SCYON Abstract

Received on January 15 2001

Hipparcos parallaxes and the distance scale of open clusters.

Authors	A.V. Loktin, G.V. Beshenov
Affiliation	Astronomical observatory of Ural State University, 51, Lenin av., Ural State University, Ekaterinburg, 620083, Russia
Accepted by	Astronomy Reports (Russia), 2001.
Contact	Alexhander.Loktin@usu.ru
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Abstract

Attempt of the determination of the distances for highest possible number of open clusters was made by the use of the values of trigonometric parallaxes from the Hipparcos catalogue. There were determined the estimates of distance moduli of 45 clusters with maximum distance from the Sun near 1 kpc. This value may be regarded as the maximum distance for the usage of Hipparcos parallaxes for the distance determinations for small groups of stars. The estimate of distance scale systematic deviation -0.157 mag was determined for the "Homogeneous catalogue of open cluster parameters" distance moduli, which appear not to depend from the cluster ages. It is interesting to note that frequency distribution of trigonometric parallaxes of Pleiades stars show two maxima, and one maximum gives the estimation of Pleiades cluster distance modulus close to the value from photometry of cluster stars.