Radial Velocities of Three Poorly Studied Clusters and the Kinematics of Open Clusters

Abstract

We present radial velocities for stars in the field of the open star clusters Berkeley 44, Berkeley 81, and NGC 6802 from spectra obtained using the Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5 m telescope. These clusters are of intermediate age (1-3 Gyr), located within the solar Galactocentric radius, and have no previous radial velocity measurements. We find mean radial velocities of -9.6 +/- 3.0 km s^-1, 48.1 +/- 2.0 km s^-1, and 12.4 +/- 2.8 km s^-1 for Be 44, Be 81, and NGC 6802, respectively. We present an analysis of radial velocities of 134 open clusters of a wide range of ages using data obtained in this study and the literature. Assuming the system of clusters rotates about the Galactic center with a constant velocity, we find older clusters exhibit a slower rotation and larger line-of-sight (LOS) velocity dispersion than younger clusters. The gradual decrease in rotational velocity of the cluster system with age is accompanied by a smooth increase in LOS velocity dispersion, which we interpret as the effect of heating on the open cluster system over time.

References in corpus (17)

• The Geneva-Copenhagen Survey of the Solar neighbourhood II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk
• Old open clusters in the outer Galactic disk
• The orbits of open clusters in the Galaxy
• Wide Field CCD photometry around nine open clusters
• CCD BV survey of 42 open clusters
• The Distances to Open Clusters from Main-Sequence Fitting. IV. Galactic Cepheids, the LMC, and the Local Distance Scale
• A New Look at the Old Star Cluster NGC 6791
• The origin and orbit of the old, metal-rich, open cluster NGC 6791: Insights from kinematics
• Element abundances in the metal rich open cluster NGC6253
• The absolute motion of the peculiar cluster NGC6791
• BVI photometry of the very old open cluster Berkeley 17
• The old open cluster NGC 2112: updated estimates of fundamental parameters based on a membership analysis
• CCD photometric search for peculiar stars in open clusters. VIII. King 21, NGC 3293, NGC 5999, NGC 6802, NGC 6830, Ruprecht 44, Ruprecht 115, and Ruprecht 120
• Fundamental parameters of six neglected old open clusters
• Trumpler 20 - an old and rich open cluster
• The anticenter old open cluster NGC 1883: radial velocity and metallicity
• Pre-main sequence stars in open clusters. I. The DAY-I catalogue

Cited by in corpus (6)

• Open clusters in APOGEE and GALAH: Combining Gaia and ground-based spectroscopic surveys
• The Gaia-ESO Survey: double, triple and quadruple-line spectroscopic binary candidates
• The Gaia-ESO Survey: Target selection of open cluster stars
• The Gaia-ESO Survey: Calibrating the lithium-age relation with open clusters and associations. I. Cluster age range and initial membership selections
• A unified model for age-velocity dispersion relations in Local Group galaxies: Disentangling ISM turbulence and latent dynamical heating
• Detailed chemical abundance analysis of the thick disk star cluster Gaia 1