Ground-based CCD astrometry with wide field imagers. II. A star catalogue for M67: [email protected] MPG/ESO astrometry, FLAMES@VLT radial velocities

Abstract

The solar-age open cluster M67 (C0847+120, NGC2682) is a touchstone in studies of the old Galactic disk. Despite its outstanding role, the census of cluster membership for M67 at fainter magnitudes and their properties are not well-established. Using the proprietary and archival ESO data, we have obtained astrometric, photometric, and radial velocities of stars in a 34'x 33' field centered on the old open cluster M67. The two-epoch archival observations separated by 4 years and acquired with the Wide Field Imager at the 2.2m MPG/ESO telescope have been reduced with our new astrometric techniques, as described in the first paper of this series. The same observations served to derive calibrated BVI photometry in M67. Radial velocities were measured using the archival and new spectroscopic data obtained at VLT. We have determined relative proper motions and membership probabilities for ~2,400 stars. The precision of proper motions for optimally exposed stars is ~2 mas/yr, gradually degrading down to ~5 mas/yr at V= 20. Our relatively precise proper motions at V>16 are first obtained in this magnitude range for M67. Radial velocities are measured for 211 stars in the same field. We also present a detailed comparison with recent theoretical isochrones from several independent groups. For M67 area we provide positions, calibrated BVI photometry, relative proper motions, membership probabilities, and radial velocities. We demonstrate that the ground-based CCD mosaic observations just a few years apart are producing proper motions, allowing a reliable membership determination. We produced a catalogue that is made electronically available to the astronomical community.

15 pages, 11 figures, 5 table. Accepted (2008 February 25) on A&A

References in corpus (7)

• Ground-Based CCD Astrometry with Wide Field Imagers. I. [Observations just a few years apart allow decontamination of field objects from members in two Globular clusters.]
• A Large Stellar Evolution Database for Population Synthesis Studies. III. Inclusion of the full Asymptotic Giant Branch phase and Web tools for stellar population analyses
• Multisite campaign on the open cluster M67. II. Evidence for solar-like oscillations in red giant stars
• A Constraint on Z_\odot from Fits of Isochrones to the Color-Magnitude Diagram of M67
• WIYN Open Cluster Study. XXVI. Improved kinematic membership and spectroscopy of IC 2391
• Tracing mixing in stars: new beryllium observations of the open clusters NGC 2516, Hyades, and M67
• Deriving temperature, mass and age of evolved stars from high-resolution spectra. Application to field stars and the open cluster IC 4651

Cited by in corpus (10)

• Spectroscopic and Photometric evidence of two stellar populations in the Galactic Globular Cluster NGC6121 (M4)
• Kinematics of the old stellar population at the Galactic Center
• Solar twins in M67
• Monte Carlo Simulations of Star Clusters - V. The globular cluster M4
• The end of the white dwarf cooling sequence in M 67
• Absolute proper motion of the Galactic open cluster M67
• Kinematic parameters and membership probabilities of open clusters in the Bordeaux PM2000 catalogue
• Ground-based CCD astrometry with wide field imagers. IV. An improved Geometric Distortion Correction for the Blue prime-focus Camera at the LBT
• Extracting parameters from Colour-Magnitude Diagrams
• Basic Parameters of Open Star Clusters DOLIDZE 14 and NGC 110 in Infrared bands