Open Clusters and Their Role in the Galaxy

Friel, Eileen D.

doi:10.1007/978-94-007-5612-0_7

Cited by 17 publications

(10 citation statements)

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“…Open clusters (OCs) are groups from several hundreds to tens of thousands of gravitationally bound stars located in the Galactic disc. Unlike more massive and complex globular clusters, all the stars of a given OC seem to share the same properties such as age, kinematics and initial chemical composition (Friel 2013). Open clusters cover a wide range of masses, luminosities, structural characteristics, and ages.…”

Section: Introductionmentioning

confidence: 99%

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Carrera

Casamiquela

Carbajo-Hijarrubia

et al. 2022

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Context. Open clusters (OCs) are widely used as test particles to investigate a variety of astrophysical phenomena, from stellar evolution to Galactic evolution. Gaia and the complementary massive spectroscopic surveys are providing an unprecedented wealth of information about these systems. Aims. The Open Cluster Chemical Abundances from Spanish Observatories (OCCASO) survey aims to complement all this work by determining OCs' accurate radial velocities and chemical abundances from high-resolution, R≥60 000, spectra. Methods. Radial velocities were obtained by cross-correlating the observed spectra with a library of synthetic spectra that covers early M to A spectral types. Results. We provide radial velocities for 336 stars including several Gaia benchmark stars and objects belonging to 51 open clusters. The internal uncertainties of the derived radial velocities go from 10 m s −1 to 21 m s −1 as a function of the instrumental configuration used. The derived radial velocities, together with the Gaia proper motions, were used to investigate the cluster membership of the observed stars. After this careful membership analysis, we obtained average velocities for 47 open clusters. To our knowledge, this is the first radial velocity determination for five of these clusters. Finally, the radial velocities, proper motions, distances and ages were used to investigate the kinematics of the observed clusters and in the integration of their orbits.

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Section: Introductionmentioning

confidence: 99%

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Carrera

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Carbajo-Hijarrubia

et al. 2022

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“…Isochrone placement becomes challenging for individual field stars, and uncertainties in the atmospheric parameters and degeneration of the models usually hinder attempts to obtain precise ages. Fortunately, placing isochrones is often much easier in clusters because they have many coeval mono-metallic members and so the results are very precise, which is why, historically, they provide the primary benchmarks we use to study age-related properties (see Friel et al 2013, for a review). Asteroseismic ages can be complementary to isochrone ages, as they can be precise (∼30% Valentini et al 2019;Miglio et al 2021) for giants, where isochrone ages cannot give a precise age given the proximity of the evolutionary tracks in the red giant branch.…”

Section: Introductionmentioning

confidence: 99%

Abundance–age relations with red clump stars in open clusters

Casamiquela

Soubiran

Jofré

et al. 2021

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Context. Precise chemical abundances coupled with reliable ages are key ingredients to understanding the chemical history of our Galaxy. Open clusters (OCs) are useful for this purpose because they provide ages with good precision. Aims. The aim of this work is to investigate the relation between different chemical abundance ratios and age traced by red clump (RC) stars in OCs. Methods. We analyzed a large sample of 209 reliable members in 47 OCs with available high-resolution spectroscopy. We applied a differential line-by-line analysis, performing a comprehensive chemical study of 25 chemical species. This sample is among the largest samples of OCs homogeneously characterized in terms of atmospheric parameters, detailed chemistry, and age. Results. In our metallicity range (−0.2 < [M/H] < +0.2) we find that while most Fe-peak and α elements show a flat dependence on age, the s-process elements show a decreasing trend with increasing age with a remarkable knee at 1 Gyr. For Ba, Ce, Y, Mo, and Zr, we find a plateau at young ages (< 1 Gyr). We investigate the relations between all possible combinations among the computed chemical species and age. We find 19 combinations with significant slopes, including [Y/Mg] and [Y/Al]. The ratio [Ba/α] shows the most significant correlation. Conclusions. We find that the [Y/Mg] relation found in the literature using solar twins is compatible with the one found here in the solar neighborhood. The age–abundance relations in clusters at large distances(d > 1 kpc) show larger scatter than those in clusters in the solar neighborhood, particularly in the outer disk. We conclude that, in addition to pure nucleosynthetic arguments, the complexity of the chemical space introduced by the Galactic dynamics must be taken into account in order to understand these relations, especially outside of the local bubble.

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“…The outer disk clusters are systematically longer lived and survive about twice as long as a typical open cluster in the inner disk. The characteristic lifetime of open clusters of all types seems to be a distinct function of galactocentric radius (Friel 2013). …”

Section: Age Distributionmentioning

confidence: 99%

Open clusters and associations in the Gaia era

Moraux

2016

EAS Publications Series

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Abstract. Open clusters and associations are groups of young stars, respectively bound and unbound, that share the same origin and disperse over time into the galactic field. As such, their formation and evolution are the key to understand the origin and properties of galactic stellar populations. Moreover, since their members have about the same age, they are ideal laboratories to study the properties of young stars and constrain stellar evolution theories.In this contribution, I present our current knowledge on open clusters and associations. I focus on the methods used to derive the statistical properties (IMF, spatial distribution, IMF) of young stars and briefly discuss how they depend on the environment. I then describe how open clusters can be used as probes to investigate the structure, dynamics and chemical composition of the Milky Way. I conclude by presenting the Gaia mission and discuss how it will revolutionize this field of research.

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Open Clusters and Their Role in the Galaxy

Cited by 17 publications

References 97 publications

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Abundance–age relations with red clump stars in open clusters

Open clusters and associations in the Gaia era

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