The young Galactic cluster NGC 225: binary stars’ content and total mass estimate

Yalyalieva, L.; Carraro, G.; Glushkova, E.; Munari, U.; Ochner, P.

doi:10.1093/mnras/stac1199

Cited by 3 publications

(3 citation statements)

References 38 publications

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“…Their identification can be done individually through photometry (as done in this work and most of the above cited papers, e.g. Niu et al 2020;Borodina et al 2021;Li & Shao 2022), but also through astrometry (Belokurov et al 2020;Penoyre et al 2022;Gaia Collaboration et al 2022a) and radialvelocity monitoring (Kobulnicky et al 2014;Bodensteiner et al 2021;Yalyalieva et al 2022). Given the number of stars in each OC and the velocity precision necessary to detect most binary systems, spectroscopic surveys typically take many years to complete.…”

Section: Discussionmentioning

confidence: 99%

The multiplicity fraction in 202 open clusters from Gaia

Donada¹,

Anders²,

Jordi³

et al. 2023

Preprint

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In this study, we estimate the fraction of binaries with high mass ratios for 202 open clusters in the extended solar neighbourhood (closer than 1.5 kpc from the Sun). This is one of the largest homogeneous catalogues of multiplicity fractions in open clusters to date, including the unresolved and total (close-binary) multiplicity fractions of main-sequence systems with mass ratio larger than 0.6 +0.05 −0.15 . The unresolved multiplicity fractions are estimated applying a flexible mixture model to the observed Gaia colour-magnitude diagrams of the open clusters. Then we use custom Gaia simulations to account for the resolved systems and derive the total multiplicity fractions. The studied open clusters have ages between 6.6 Myr and 3.0 Gyr and total high-mass-ratio multiplicity fractions between 6% and 80%, with a median of 18%. The multiplicity fractions increase with the mass of the primary star, as expected. The average multiplicity fraction per cluster displays an overall decreasing trend with the open cluster age up to ages about 100 Myr, above which the trend increases. Our simulations show that most of this trend is caused by complex selection effects (introduced by the mass dependence of the multiplicity fraction and the magnitude limit of our sample). Furthermore, the multiplicity fraction is not significantly correlated with the clusters' position in the Galaxy. The spread in multiplicity fraction decreases significantly with the number of cluster members (used as a proxy for cluster mass). We also find that the multiplicity fraction decreases with metallicity, in line with recent studies using field stars.

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Section: Discussionmentioning

confidence: 99%

The multiplicity fraction in 202 open clusters from Gaia

Donada¹,

Anders²,

Jordi³

et al. 2023

Preprint

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“…Only data with parallax errors smaller than 20% were taken into account. We used the same technique described in Yalyalieva et al (2022), namely a Python implementation of the Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm provided by the SCIKIT-LEARN library (Pedregosa et al 2011). DBSCAN requires two main parameters-eps, the maximum distance between two points for one of them to be considered a neighbor of the other; and min_samples, the minimum number of points in the neighborhood of a particular point for this to be considered a core point.…”

Section: Clustering Algorithmmentioning

confidence: 99%

“…The results of the radial velocities extraction are presented in Tables 8, 9, and 10 for FSR 866, NGC 1960, and Stock 2, respectively, and in Figure 10. In order to select binary stars, we used the following criteria (Yalyalieva et al 2022):…”

Section: Binary Fraction According To Spectroscopy and Mean Radial Ve...mentioning

confidence: 99%

Binary Fraction in Galactic Star Clusters: FSR 866, NGC 1960, and STOCK 2

Yalyalieva,

Chemel,

Carraro

et al. 2024

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The study of binary stars in different astronomical environments offers insights into the dynamical state of the hosting stellar systems. The binary fraction in fact plays a crucial role in the dynamical evolution of stellar systems, regulating processes like mass segregation and dynamical heating, and in some cases leading to the formation of exotic objects, like, for instance, blue straggler stars. We used two methodologies to estimate the binary fraction in three different-age open star clusters: FSR 866, NGC 1960 (M36), and Stock 2. The first is a photometric approach based on color–magnitude diagram analysis, and the second is a spectroscopic technique that employs radial velocity measurements. We used Gaia DR3 data in tandem with new spectroscopic observations, and employed the Density-Based Spatial Clustering of Applications with Noise algorithm to identify probable cluster members based on proper motion and parallax in 3D space. The new sample of cluster members allows us to provide new estimates of the cluster fundamental parameters. As a by-product, we found two previously undetected, small physical groups of stars in the background of NGC 1960. The resulting binary fractions lie in the range 0.3–0.5 and are in good agreement with those expected theoretically for open clusters.

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Revisiting the mass of open clusters with Gaia data

Almeida

Monteiro

Dias

2023

Monthly Notices of the Royal Astronomical Society

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The publication of the Gaia catalogue and improvements in methods to determine memberships and fundamental parameters of open clusters has led to major advances in recent years. However, important parameters such as the masses of these objects, although being studied mostly in some isolated cases, have not been addressed in large homogeneous samples based on Gaia data, taking into account details such as binary fractions. Consequently, relevant aspects such as the existence of mass segregation were not adequately studied. Within this context, in this work, we introduce a new method to determine individual stellar masses, including an estimation for the ones in binary systems. This method allows us to study the mass of open clusters, as well as the mass functions of the binary star populations. We validate the method and its efficiency and characterize uncertainties using a grid of synthetic clusters with predetermined parameters. We highlight the application of the method to the Pleiades cluster, showing that the results obtained agree with the current consensus in the literature as well as recent Gaia data. We then applied the procedure to a sample of 773 open clusters with fundamental parameters determined using Gaia Early Data Release 3 (eDR3) data, obtaining their masses. Subsequently, we investigated the relation between the masses and other fundamental parameters of the clusters. Among the results, we found no significant evidence that clusters in our sample lose and segregate mass with age.

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The young Galactic cluster NGC 225: binary stars’ content and total mass estimate

Cited by 3 publications

References 38 publications

The multiplicity fraction in 202 open clusters from Gaia

The multiplicity fraction in 202 open clusters from Gaia

Binary Fraction in Galactic Star Clusters: FSR 866, NGC 1960, and STOCK 2

Revisiting the mass of open clusters with Gaia data

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