J/PAZh/25/10 Young open clusters space-age distribution (Dambis, 1999)
Space-age distribution of young open clusters and observational selection.
Dambis A.K.
<Pis'ma Astron. Zh. 25, 10 (1999)>
=1999PAZh...25...10D 1999PAZh...25...10D
=1999AstL...25....7D 1999AstL...25....7D
ADC_Keywords: Clusters, open; Combined data
Abstract:
Based on published photoelectric and CCD photometry and using the
empirical ZAMS of Kholopov (1980, AZh, 57, 12) and the
evolutionary-deviation curves obtained from the grid of isochrones
computed by Maeder and Meynet (1991A&AS...89..451M 1991A&AS...89..451M), we determine the
distances, color excesses, and ages for 203 Galactic open clusters
with logt<8.2. The validity of the derived distance scale is
corroborated by the Hipparcos trigonometric parallaxes of seven
clusters. The age distribution of the clusters is distorted by
observational selection, which is enhanced with increasing
heliocentric distance and which is virtually independent of
interstellar extinction. As a result, the youngest (logt≤7.5)
clusters are represented almost exclusively at heliocentric distances
>2kpc, and the mean age of the cataloged clusters with logt≤100Myr
decreases from 50Myr in the solar neighborhood down to 15Myr at
heliocentric distances >2.4kpc.
Description:
As the observation material, we used all the available published
photoelectric and CCD UBV photometry of Galactic clusters collected in
the database of Mermilliod (1988BICDS..35...77M 1988BICDS..35...77M, 1992BICDS..40..115M 1992BICDS..40..115M,
http://www.univie.ac.at/webda) and the photoelectric UBV photometry of
stats in the WZ Sgr cluster field obtained by Berdnikov (1995, priv.
comm.).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 39 202 Parameters of open clusters
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See also:
J/other/A+AT/25.185 : Globular clusters absolute proper motions (Dambis, 2006)
http://www.univie.ac.at/webda : WEDBA Home Page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Cluster name
18- 22 F5.2 mag DM0 True distance modulus
24- 27 F4.2 mag e_DM0 Error of true distance modulus
30- 34 F5.3 mag E(B-V) E(B-V) color excess
36- 39 F4.2 [yr] log(age) Logarithm of cluster age
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Acknowledgements:
Andrei Dambis, dambis(at)yandex.ru
(End) Andrei Dambis [SAI, Russia], Patricia Vannier [CDS] 03-Feb-2014