Volume 484, Number 2, June III 2008
|Page(s)||609 - 620|
|Section||Catalogs and data|
|Published online||19 March 2008|
II. A star catalog for M 67: WFI@2.2 m MPG/ESO astrometry, FLAMES@VLT radial velocities
Dipartimento di Astronomia, Universita di Padova, Vicolo dell' Osservatorio 2, 35122 Padova, Italy e-mail: [giampaolo.piotto;sandro.villanova]@unipd.it
2 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA e-mail: [bedin;jander]@stsci.edu
3 INAF – Osservatorio Astronomico di Collurania, via M. Maggini, 64100 Teramo, Italy e-mail: email@example.com
4 Grupo de Astronomía, Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción, Chile e-mail: firstname.lastname@example.org
5 Dept. of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218, USA e-mail: email@example.com
6 European Southern Observatory, Garching, Karl-Schwarzschild-Str. 2, 85748 Germany e-mail: firstname.lastname@example.org
7 INAF – Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35132, Italy e-mail: email@example.com
8 Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263 129, India e-mail: firstname.lastname@example.org
Corresponding author: email@example.com
Accepted: 25 February 2008
Context. The solar-age open cluster M 67 (C0847+120, NGC 2682) is a touchstone in studies of the old Galactic disk. Despite its outstanding role, the census of cluster membership for M 67 at fainter magnitudes and their properties are not well-established.
Aims. Using proprietary and archival ESO data, we have obtained astrometric, photometric, and radial velocities of stars in a arcmin2 field centered on the old open cluster M 67.
Methods. The two-epoch archival observations separated by 4 years and acquired with the Wide-Field Imager at the 2.2 m MPG/ESO telescope were reduced with our new astrometric techniques, as described in the first paper in this series. The same observations served to derive calibrated BVI photometry in M 67. Radial velocities were measured using the archival and new spectroscopic data obtained at the VLT.
Results. We have determined relative proper motions and membership probabilities for ~2400 stars. The precision of proper motions for optimally exposed stars is 1.9 mas yr-1, gradually degrading down to ~5 mas yr-1 at . Our relatively precise proper motions at were first obtained in this magnitude range for M 67. Radial velocities were measured for 211 stars in the same field. We also present a detailed comparison with recent theoretical isochrones from several independent groups.
Conclusions. For the M 67 area, we provide positions, calibrated BVI photometry, relative proper motions, membership probabilities, and radial velocities. We demonstrate that ground-based CCD mosaic observations just a few years apart are producing proper motions, allowing reliable membership determination. We have produced a catalog that is electronically available to the astronomical community.
Key words: Galaxy: open clusters and associations: individual: M 67 / astrometry / catalogs
Based on observations with the MPG/ESO 2.2 m and ESO/VLT telescopes, located at La Silla and Paranal Observatory, Chile, under DDT program 278.D-5027, and the archive material.
© ESO, 2008
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.