Development of the Galactic disk: A search for the oldest open clusters

Phelps, Randy L.; Janes, K. A.; Montgomery, Kent A.

doi:10.1086/116920

Cited by 139 publications

(186 citation statements)

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“…In the database, the R GC were taken from Friel et al (1995Friel et al ( , 2002Friel et al ( , 2006 or calculated using the cluster distance given in the original papers and a solar Galactocentric distance of 8.5 kpc, consistent with Friel et al works. The ages for the clusters older than 0.5−0.6 Gyr were calculated in an homogeneous way using the morphological age indicator δV (Phelps et al 1994) and the metallicity-dependent calibration of Salaris et al (2004). For the younger clusters, M09 used the most recent age determinations available in the literature, such as those obtained with the lithium-depletion boundary method.…”

Section: The Metallicity Gradient Of Open Clustersmentioning

confidence: 99%

Open clusters towards the Galactic centre: chemistry and dynamics

Magrini

Randich

Zoccali

et al. 2010

A&A

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Context. In the framework of the study of the Galactic metallicity gradient and its time evolution, we present new high-resolution spectroscopic observations obtained with FLAMES and the fiber link to UVES at VLT of three open clusters (OCs) located within ∼7 kpc from the Galactic centre (GC): NGC 6192, NGC 6404, NGC 6583. We also present new orbit determination for all OCs with Galactocentric distances (R GC ) ≤ 8 kpc and metallicity from high-resolution spectroscopy. Aims. We aim to investigate the slope of the inner disc metallicity gradient as traced by OCs and to discuss its implication for the chemical evolution of our Galaxy. Methods. We have derived memberships of a group of evolved stars for each clusters, obtaining a sample of 4, 4, and 2 member stars in NGC 6192, NGC 6404, and NGC 6583, respectively. Using standard LTE analysis we derived stellar parameters and abundance ratios for the iron-peak elements Fe, Ni, Cr, and for the α-elements Al, Mg, Si, Ti, Ca. We calculated the orbits of the OCs currently located within 8 kpc from the GC, and discuss their implication on the present-time radial location. Results. The average metallicities of the three clusters are all oversolar: [Fe/H] = +0.12±0.04 (NGC 6192), +0.11±0.04 (NGC 6404), +0.37 ± 0.03 (NGC 6583). They are in qualitative agreement with their Galactocentric distances, because they are all internal OCs, and expected to be more metal rich than the solar neighbourhood. The abundance ratios of the other elements over iron [X/Fe] are consistent with solar values. Conclusions. The clusters we have analysed confirm, together with other OC and Cepheid data, a steep gradient in the inner disc, a signature of an evolutionary rate that is different from the one in the outer disc.

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Section: The Metallicity Gradient Of Open Clustersmentioning

confidence: 99%

Open clusters towards the Galactic centre: chemistry and dynamics

Magrini

Randich

Zoccali

et al. 2010

A&A

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“…Cr 261 is the oldest of the southern open clusters identified in Phelps et al (1994). It is a rich cluster located at l = 302 and b = À5=6, 7.5 kpc from the Galactic center and 235 pc below the plane.…”

Section: Properties Of Cr 261mentioning

confidence: 99%

“…Based on the photometry of Phelps et al (1994), used the morphology of the colormagnitude diagram to determine an age of 9.5 Gyr on their morphological age indicator scale, making Cr 261 the second oldest open cluster known in the Galaxy. They also found a reddening E(BÀV ) of 0.33 based on a comparison of the observed color of the red giant clump to a fiducial intrinsic value.…”

Section: Properties Of Cr 261mentioning

confidence: 99%

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Abundances of Red Giants in the Old Open Cluster Collinder 261

et al. 2003

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“…One can see from this figure that there are very few OCs at the galactocentric distances less than 5 kpc. Furthermore, while young clusters (with ages less than 0.8 Gyr; see Phelps et al 1994) are distributed quite uniformly around the Sun, most of the older OCs are distributed in the outer part of the disk. Such apparent distributions are partially due to the much higher extinction in the direction of Galactic Center and the deficiency of older clusters in the inner part of the disk, that has been attributed to the preferential destruction of these clusters by giant molecular clouds, which are primarily found in the inner Galaxy.…”

Section: Spatial and Kinematic Properties Of Galactic Open Clustersmentioning

confidence: 99%

Open clusters: their kinematics and metallicities

et al. 2007

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Abstract. We review our work on Galactic open clusters in recent years, and introduce our proposed large program for the LOCS (LAMOST Open Cluster Survey). First, based on the most complete open clusters sample with metallicity, age and distance data as well as kinematic information, some preliminary statistical analysis regarding the spatial and metallicity distributions is presented. In particular, a radial abundance gradient of −0.058± 0.006 dex kpc −1 is derived. By dividing clusters into the age groups we show that the disk abundance gradient was steeper in the past. Secondly, proper motions, membership probabilities, and velocity dis- The open cluster system and the observational databaseOpen clusters (OCs) are considered excellent laboratories for studies of stellar evolution. Studies in the research area dealing with OCs show a rapid growth in 1990's and this area continues to develop vigorously. There may be several reasons for this recent growth of OC studies. New techniques are greatly beneficial to the OC observations, including, for example, the application of wide-field, high quality CCD cameras and, more recently, multi-object spectrographs. In addition, OC studies play a very important and unique role in determining the structure and evolution of the Galactic disk.OCs have long been used to trace the structure and evolution of the Galactic disk. From the observational point of view, there are some important advantages of using OCs as opposed to field stars. In OCs, we deal with groups of stars of nearly the same age, a similar composition and at a similar distance. We can observe OCs to large distances, and the photometric distances to most of the OC sample have already been derived. In particular, OCs have a relatively stable orbital motion, which can be used as a better tracer of the Galactic disk structure. OCs also have a wide range of ages, so that -combined with their spatial distribution and kinematic information -we can study the effects of dynamical evolution. Very young OCs are ideal objects for studies of the stellar initial mass function. Furthermore, when combined with abundance data, we can 433 at https://www.cambridge.org/core/terms. https://doi

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Development of the Galactic disk: A search for the oldest open clusters

Cited by 139 publications

References 0 publications

Open clusters towards the Galactic centre: chemistry and dynamics

Open clusters towards the Galactic centre: chemistry and dynamics

Abundances of Red Giants in the Old Open Cluster Collinder 261

Open clusters: their kinematics and metallicities

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