Issue |
A&A
Volume 470, Number 2, August I 2007
|
|
---|---|---|
Page(s) | 585 - 596 | |
Section | Galactic structure, stellar clusters, and populations | |
DOI | https://doi.org/10.1051/0004-6361:20067003 | |
Published online | 10 May 2007 |
uvby – H
CCD photometry and membership segregation of the open cluster NGC 2682 (M 67) *,**
1
Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Avda. Diagonal 647, 08028 Barcelona, Spain e-mail: Lola.Balaguer@am.ub.es
2
Shanghai Astronomical Observatory, CAS Shanghai 200030, PR China
3
Institute of Astronomy, Madingley Road, CB3 OHA Cambridge, UK
4
Instituto de Astrofísica de Andalucía (CSIC). Camino Bajo de Huétor 50, 18008 Granada, Spain
5
Institut d'Estudis Espacials de Catalunya - IEEC, Edif. Nexus Gran Capità 2-4, 08034 Barcelona, Spain
Received:
21
December
2006
Accepted:
13
April
2007
Following deep astrometric and photometric study of the cluster
NGC 2682 (M 67), we are able to accurately determine its fundamental
parameters. Being an old and rich cluster, M 67 is relevant
for the analysis of the Galactic disk evolution.
M 67 is well studied but lacks a wide and deep
Strömgren photometric study. The brightest stars of the open cluster M 67 were used as
uvby-H standard stars in our studies of NGC 1817
and NGC 2548, and the extension of the field covered, as well as the
number of observations, allowed us to obtain the best set of
Strömgren data ever published for this cluster.
We discuss the results of our CCD uvby-H
intermediate-band
photometry, covering an area of about 50′
50′
down to V ~ 19. Moreover, a complete membership segregation
based on astrometric and photometric criteria is obtained.
The photometric analysis of a selected sample of stars yields a reddening value of
= 0.03 ± 0.03, a distance modulus of
= 9.7 ± 0.2 and [Fe/H] = 0.01 ± 0.14.
Through isochrone fitting we found an age of log t = 9.6 ± 0.1
(4.2 ± 0.2 Gyr). A clump of approximately 60 stars around
V = 16,
= 0.4 could be interpreted as a population
of pre-cataclysmic variable stars (if members), or as a stream of
field G-type stars placed at twice
the distance of the cluster (if non-members).
Key words: Galaxy: open clusters and associations: individual: NGC 2682 / techniques: photometric / astrometry / methods: observational / methods: data analysis
© ESO, 2007
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