Binary star sequence in the outskirts of the disrupting Galactic open cluster UBC 274

Piatti, Andrés E.

doi:10.1051/0004-6361/202038239

Cited by 7 publications

(9 citation statements)

References 30 publications

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“…Of the 75 high-confidence clusters recently discovered by Liu & Pang (2019), 35 are present in the latest catalogue from Cantat-Gaudin et al ( 2020), and we provide an RV for most of them. For instance, we provide the mean RV of UBC 274 (also reported as LP 5), a recently discovered disrupting OC (Castro-Ginard et al 2020;Piatti 2020), based on 18 members observed with RAVE, GALAH, and Gaia RVS (Fig. 3).…”

Section: Mean Rvsmentioning

confidence: 99%

3D kinematics and age distribution of the open cluster population

Tarricq

Soubiran

Casamiquela

et al. 2021

A&A

135

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Context. Open clusters (OCs) trace the evolution of the Galactic disc with great accuracy. Gaia and large ground-based spectroscopic surveys make it possible to determine their properties and study their kinematics with unprecedented precision. Aims. We study the kinematical behaviour of the OC population over time. We take advantage of the latest age determinations of OCs to investigate the correlations of the 6D phase-space coordinates and orbital properties with age. The phase-space distribution, age-velocity relation, and action distribution are compared to those of field stars. We also investigate the rotation curve of the Milky Way traced by OCs, and we compare it to that of other observational or theoretical studies. Methods. We gathered nearly 30 000 radial velocity (RV) measurements of OC members from both Gaia-RVS data and ground-based surveys and catalogues. We computed the weighted mean RV, Galactic velocities, and orbital parameters of 1382 OCs. We investigated their distributions as a function of age and by comparison to field stars. Results. We provide the largest RV catalogue available for OCs, half of it based on at least three members. Compared to field stars, we note that OCs are not on exactly the same arches in the radial-azimuthal velocity plane, while they seem to follow the same diagonal ridges in the Galactic radial distribution of azimuthal velocities. Velocity ellipsoids in different age bins all show a clear anisotropy. The heating rate of the OC population is similar to that of field stars for the radial and azimuthal components, but it is significantly lower for the vertical component. The rotation curve drawn by our sample of clusters shows several dips that match the wiggles derived from nonaxisymmetric models of the Galaxy. From the computation of orbits, we obtain a clear dependence of the maximum height and eccentricity on age. Finally, the orbital characteristics of the sample of clusters as shown by the action variables follow the distribution of field stars. The additional age information of the clusters indicates some (weak) age dependence of the known moving groups.

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Section: Mean Rvsmentioning

confidence: 99%

3D kinematics and age distribution of the open cluster population

Tarricq

Soubiran

Casamiquela

et al. 2021

A&A

135

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“…The intrinsic CMD effectively reduces the scatter along the main sequence and highlights a very remarkable equal-mass binary sequence, as analysed by Piatti (2020), but in a larger magnitude range. We notice some possible contaminants at the faint left side of the main sequence (corresponding to apparent magnitudes 17-19), in agreement with the studied recovery statistics where we can expect contamination of 30% (Fig.…”

Section: Cluster Age and Extinctionmentioning

confidence: 87%

“…Later, Piatti (2020) found that the cluster is affected by differential reddening, which ranges from E B−V = 0.1 -0.25. They found log Age = 9.45 ± 0.05 (2.8 ± 0.2 Gyr) provides the best fit to their CMD using the PARSEC isochrones (Bressan et al 2012), with a compromise between the agreement of the turnoff and the red clump.…”

Section: Cluster Age and Extinctionmentioning

confidence: 99%

Unravelling UBC 274: A morphological, kinematical, and chemical analysis of a disrupting open cluster

Casamiquela

Olivares

Tarricq

et al. 2022

A&A

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Context. Open clusters in the process of disruption help to understand the formation and evolution of the Galactic disk. The wealth and homogeneity of Gaia data have led to the discovery of several open clusters with signs of disruption. Detailed chemical information for these clusters is essential in order to study the timescales and interplay between the star formation process and cluster disruption. Aims. We perform a morphological, kinematic, and chemical analysis of the disrupting cluster UBC 274 (2.5 Gyr, d = 1778 pc), to study its global properties. Methods. We use HDBSCAN to obtain a new membership list up to 50 pc from its centre and up to magnitude G = 19 using Gaia EDR3 data. We use high-resolution and high signal-to-noise spectra to obtain atmospheric parameters of six giants and sub-giants, and individual abundances of 18 chemical species. Results. The cluster has a highly eccentric (0.93) component, tilted ∼10 deg with respect to the plane of the Galaxy, which is morphologically compatible with the results of a test-particle simulation of a disrupting cluster. Our abundance analysis shows that the cluster has a sub-solar metallicity of [Fe/H] = −0.08 ± 0.02. Its chemical pattern is compatible with that of Ruprecht 147, of similar age but located closer to the Sun, with the remarkable exception of neutron-capture elements, which present an overabundance of [n/Fe] ∼ 0.1. Conclusions. The cluster's elongated morphology is associated with the internal part of its tidal tail, following the expected dynamical process of disruption. We find a significant sign of mass segregation, where the most massive stars appear 1.5 times more concentrated than other stars. The cluster's overabundance of neutron-capture elements can be related to the metallicity dependence of the neutron-capture yields due to the secondary nature of these elements, predicted by some models. UBC 274 presents a high chemical homogeneity at the level of 0.03 dex in the sampled region of its tidal tails.

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“…Finally, we would like to mention that extra-tidal stars should have distinct velocities that make it possible for them to escape the cluster. Likewise, they are at different Galactocentric distances than the cluster itself, so that they are differently affected by the Milky Way gravitational field (Piatti 2020;Dinnbier & Kroupa 2020).…”

Section: Discussionmentioning

confidence: 99%

The elusive tidal tails of the Milky Way globular cluster NGC 7099

Piatti

Carballo‐Bello

Mora

et al. 2020

A&A

Self Cite

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We present results on the extra-tidal features of the Milky Way globular cluster NGC 7099, using deep gr photometry obtained with the Dark Energy Camera (DECam). We reached nearly 6 mag below the cluster’s main sequence (MS) turnoff, so that we dealt with the most suitable candidates to trace any stellar structure located beyond the cluster tidal radius. From star-by-star reddening corrected color-magnitude diagrams (CMDs), we defined four adjacent strips along the MS, for which we built the respective stellar density maps, once the contamination by field stars was properly removed. The resulting, cleaned, field star stellar density maps show a short tidal tail and some scattered debris. Such extra-tidal features are hardly detected when much shallower Gaia DR2 data sets are used and the same CMD field star cleaning procedure is applied. Indeed, by using 2.5 mag below the MS turnoff of the cluster as the faintest limit (G < 20.5 mag), cluster members turned out to be distributed within the cluster’s tidal radius, and some hints for field star density variations are found across a circle of radius 3.5° centered on the cluster and with similar CMD features as cluster stars. The proper motion distribution of these stars is distinguishable from that of the cluster, with some superposition, which resembles that of stars located beyond 3.5° from the cluster center.

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Binary star sequence in the outskirts of the disrupting Galactic open cluster UBC 274

Cited by 7 publications

References 30 publications

3D kinematics and age distribution of the open cluster population

3D kinematics and age distribution of the open cluster population

Unravelling UBC 274: A morphological, kinematical, and chemical analysis of a disrupting open cluster

The elusive tidal tails of the Milky Way globular cluster NGC 7099

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