An Investigation of Poorly Studied Open Cluster NGC 4337 Using Multicolor Photometric and Gaia DR2 Astrometric Data

A Gaia based analysis of open cluster Berkeley 27

We present an analysis of three southern open star clusters NGC 6067, NGC 2506, and IC 4651 using wide-field photometric and Gaia DR2 astrometric data. They are poorly studied clusters. We took advantage of the synergy between Gaia DR2 high precision astrometric measurements and ground-based wide-field photometry to isolate cluster members and further study these clusters. We identify the cluster members using proper motions, parallax and colour–magnitude diagrams. Mean proper motion of the clusters in μαcosδ and μδ is estimated as −1.90 ± 0.01 and −2.57 ± 0.01 mas yr−1 for NGC 6067, −2.57 ± 0.01, and 3.92 ± 0.01 mas yr−1 for NGC 2506 and −2.41 ± 0.01 and −5.05 ± 0.02 mas yr−1 for IC 4651. Distances are estimated as 3.01 ± 0.87, 3.88 ± 0.42, and 1.00 ± 0.08 kpc for the clusters NGC 6067, NGC 2506, and IC 4651, respectively, using parallaxes taken from Gaia DR2 catalogue. Galactic orbits are determined for these clusters using Galactic potential models. We find that these clusters have circular orbits. Cluster radii are determined as 10 arcmin for NGC 6067, 12 arcmin for NGC 2506, and 11 arcmin for IC 4651. Ages of the clusters estimated by isochrones fitting are 66 ± 8 Myr, 2.09 ± 0.14 Gyr, and 1.59 ± 0.14 Gyr for NGC 6067, NGC 2506, and IC 4651, respectively. Mass function slope for the entire region of cluster NGC 2506 is found to be comparable with the Salpeter value in the mass range of 0.77–1.54 M⊙. The mass function analysis shows that the slope becomes flat when one goes from halo to core region in all the three clusters. A comparison of dynamical age with cluster’s age indicates that NGC 2506 and IC 4651 are dynamically relaxed clusters.

This paper presents an investigation into the four open clusters Czernik 14, Haffner 14, Haffner 17 and King 10, located near the Perseus arm of the Milky Way, using the Gaia DR2, 2MASS, WISE, APASS and Pan-STARRS1 data sets. We find normal interstellar extinction in 12 photometric bands for these clusters. Using Gaia DR2 proper motion data, the numbers of likely cluster members are found to be 225, 353, 350 and 395 for Czernik 14, Haffner 14, Haffner 17 and King 10, respectively. Radii are determined as 3.5, 3.7, 6.2 and 5.7 arcmin for Czernik 14, Haffner 14, Haffner 17 and King 10, respectively. Mean proper motions in RA and Dec. are estimated as (−0.42 ± 0.02, −0.38 ± 0.01), (−1.82 ± 0.009, 1.73 ± 0.008), (−1.17 ± 0.007, 1.88 ± 0.006) and (−2.75 ± 0.008, −2.04 ± 0.006) mas yr−1 for Czernik 14, Haffner 14, Haffner 17 and King 10, respectively. The comparison of observed colour–magnitude diagrams with solar metallicity isochrones leads to ages of 570 ± 60, 320 ± 35, 90 ± 10 and 45 ± 5 Myr for these clusters. The distances of 2.9 ± 0.1, 4.8 ± 0.4, 3.6 ± 0.1 and 3.8 ± 0.1 kpc determined using parallax are similar to the values derived by the isochrone-fitting method. Mass function slopes are found to be in good agreement with the Salpeter value. The total masses are derived as 348, 595, 763 and 1088 M⊙ for Czernik 14, Haffner 14, Haffner 17 and King 10, respectively. Evidence for the existence of a mass-segregation effect is observed in each cluster. Using the Galactic potential model, Galactic orbits are derived for the clusters. It is found that all four clusters follow a circular path around the Galactic Centre.

This paper presents a deep investigation of two open clusters, Haffner 22 and Melotte 71, using astrometric and photometric data from Gaia EDR3. We identified 382 and 597 most probable cluster members with membership probability higher than 50%. Mean proper motions in R.A. and decl. are estimated as (−1.631 ± 0.009, 2.889 ± 0.008) and (−2.398 ± 0.004, 4.210 ± 0.005) mas yr−1 for Haffner 22 and Melotte 71, respectively. A comparison of observed CMDs with the theoretical isochrones leads to an age of 2.25 ± 0.25 and 1.27 ± 0.14 Gyr for these clusters. The distances 2.88 ± 0.10 and 2.28 ± 0.15 kpc based on the parallax are comparable with the values derived by the isochrone fitting method. Five and four blue straggler stars (BSS) are identified as cluster members in Haffner 22 and Melotte 71. Based on the relative number of high-velocity (binary) and single stars, we inferred binary fractions for both clusters in the range of ∼10% ≤ f bin ≤ 14%, for both core and o?-core regions. We found binary content is larger in the core region. Mass function slope is in good agreement with the Salpeter’s value for Melotte 71 (x = 1.23 ± 0.38 within mass range 1–3.4 M ⊙) while it is quite a flat slope for Haffner 22 (x = 0.63 ± 0.30 within mass range 1–2.3 M ⊙). Evidence for the existence of mass-segregation effect is observed in both clusters. Using the Galactic potential model, Galactic orbits are derived, indicating that both clusters follow a circular path around the Galactic center, evolving slowly.

We present a comprehensive study of the young open cluster King 13 using photometric and astrometric data from Gaia DR3 and 2MASS. Our analysis refines the cluster’s fundamental parameters, including its structure, kinematics, and evolutionary status. To assess membership, we employed thepyUPMASKPython package with the HDBSCAN algorithm. The primary emphasis of this study is our new approach to assign a membership probability at each radius, rather than applying a single value to the entire cluster. These probabilities are calculated based on the number of stars deduced from the King model. This revealed a dense core with an elongated halo aligned with the cluster’s tangent velocity. Cluster orbital analysis suggests the cluster moves in the Galactic plane toward the Galactic center, with its tidal tail aligned with orbital motion-likely due to Galactic tidal effects. We identified 1571 41 member stars with a total mass of 2658.4 61.5 M. The mass function (MF) for the cluster has been constructed using a step function with two power lows, and , rather than the single power low suggested by Salpeter. In this cluster, the and are found to be -3.70.4 and 2.3 0.15 , respectively. . The cluster’s physical parameters were derived using PARSEC stellar isochrones, estimating an age of 310 28 Myr and a relaxation time of 134 13 Myr, indicating dynamical stability. The proper motions (, ) and parallax () were measured as -2.64 0.36 mas yr, -0.89 0.25 mas yr, and 0.245 0.05 mas, respectively. The corresponding distance of the cluster, derived from the parallax, is 4082 231 pc. The derived distance modulus is 13.11 1.03 mag ( 4187 262 pc), with color excess values of 1.17 0.07 mag (Gaia) and 0.44 0.03 mag (2MASS), further validating our results. Additionally, 46 member stars with radial velocity data allowed us to compute the cluster’s orbit using the galpy package. Our findings highlight the presence of a tidal tail directed toward the center of the Galaxy and underscore the role of Galactic tidal forces in shaping King 13’s morphology, reinforcing its importance in the evolution of open clusters.

This paper investigates a poorly studied open cluster, NGC 5288, using 2MASS JHKS and the recently released Gaia DR3 astrometric and photometric data. The mean proper motions in right ascension and declination are estimated as (-3.840 ± 0.230) and (-1.934 ± 0.162) mas yr-1 respectively. We also derive the age and distance of the cluster as 510 ± 190 Myr and 2.64 ± 0.11 kpc, using color-magnitude diagrams (CMDs). We also obtain the distance as 2.77 ± 0.42 kpc using the parallax method. Interstellar reddening E(B ‒ V) in the direction of the cluster is determined as 0.45 mag using the ((J ‒ H), (J ‒ K)) color-color diagram. We find the mass function slope for main-sequence stars as 1.39 ± 0.29 within the mass range 1.0-2.7 M☉, which agrees with Salpeter's value within the uncertainty. Galactic orbits are derived using the Galactic potential model, indicating that NGC 5288 follows a circular path around the Galactic center.

We present a detailed photometric and kinematical analysis of the poorly studied open cluster IC 1434 using CCD VRI, APASS, and Gaia DR2 database for the first time. By determining the membership probability of stars we identify the 238 most probable members with a probability higher than 60%; by using proper motion and parallax data as taken from the Gaia DR2 catalog. The mean proper motion of the cluster is obtained as μx=−3.89±0.19 and μy=−3.34±0.19 mas yr−1 in both the directions of right ascension and declination. The radial distribution of member stars provides the cluster extent as 7.6 arcmin. We estimate the interstellar reddening E(B−V) as 0.34 mag using the transformation equations from the literature. We obtain the values of cluster age and distance as 631±73 Myr and 3.2±0.1 kpc.

We present a CCD UBVI photometric study of poorly studied intermediate-age open cluster SAI 35 (Juchert 20) for the first time. To accomplish this study, we also used LAMOST DR5, Two Micron All Sky Survey, and Gaia EDR3 databases. We identified 214 most probable cluster members with membership probability higher than 50%. The mean proper motion of the cluster is found as and μ δ = −1.66 ± 0.01 mas yr−1. We find the normal interstellar extinction law using the various two-color diagrams. The age, distance, reddening, and radial velocity of the cluster are estimated to be 360 ± 40 Myr, 2.9 ± 0.15 kpc, 0.72 ± 0.05 mag, and −91.62 ± 6.39 km s−1, respectively. The overall mass function slope for main-sequence stars is found to be 1.49 ± 0.16 within the mass range 1.1–3.1 M ⊙, which is in agreement with Salpeter’s value within uncertainty. The present study demonstrates that SAI 35 is dynamically relaxed. Galactic orbital parameters are determined using Galactic potential models. We found that this object follows a circular path around the Galactic center.

The membership determination for open clusters in noisy environments of the Milky Way is still an open problem. In this paper, our main aim is to provide the membership probability of stars using proper motions and parallax values of stars using Gaia Third Data Release astrometry. Apart from the Gaia astrometry, we have also used other photometric data sets like the UKIRT Infrared Deep Sky Survey, WISE, the American Association of Variable Star Observers (AAVSO) Photometric All-Sky Survey, and Pan-STARRS1 in order to understand cluster properties from optical to mid-infrared regions. We selected 438 likely members with membership probabilities higher than $50\%$ and G ≤ 20 mag. We obtained the mean value of proper motion as μx = 1.27 ± 0.001 and μy = −0.73 ± 0.002 mas yr−1. The cluster’s radius is determined as ${7{^{\prime }_{.}}5}$ (5.67 pc) using radial density profile. Our analysis suggests that NGC 1348 is located at a distance of 2.6 ± 0.05 kpc. The mass function slope is found to be 1.30 ± 0.18 in the mass range 1.0–4.1 M⊙, which is in fair agreement with Salpeter’s value within the 1σ uncertainty. The present study validates that NGC 1348 is a dynamically relaxed cluster. We computed the apex coordinates (A, D) for NGC 1348 as (A°, D°) = (−23.°815 ± 0.°135, −22.°228 ± 0.°105). In addition, calculations of the velocity ellipsoid parameters (VEPs), matrix elements μij, direction cosines (lj, mj, nj), and the galactic longitude of the vertex have been conducted in this analysis.

In this study, we utilize photometric and kinematic data from Gaia DR3 and the ASteCA package to analyze the sparsely studied open clusters, King 2 and King 5. For King 2, we identify 340 probable members with membership probabilities exceeding 50%. Its mean proper motion components are determined as ( μ α cos δ , μ δ ) = ( − 1.407 ± 0.008 , − 0.863 ± 0.012 ) mas yr−1, and its limiting radius is derived as 6.94 − 1.06 + 0.22 arcminutes based on radial density profiles. The cluster has an estimated age of 4.80 ± 0.30 Gyr, a distance of 6586 ± 164 pc, and a metallicity of [Fe/H] = −0.25 dex (z = 0.0088). We detect 17 blue straggler stars (BSSs) concentrated in its core, and its total mass is estimated to be 356 ± 19M ⊙. The computed apex motion is ( A o , D o ) = ( − 14 2 . ∘ 61 ± 0 . ∘ 08 , − 6 3 . ∘ 58 ± 0 . ∘ 13 ) . Similarly, King 5 consists of 403 probable members with a mean proper motion components ( μ α cos δ , μ δ ) = ( − 0.291 ± 0.005 , − 1.256 ± 0.005 ) mas yr−1 and a limiting radius of 11.33 − 2.16 + 5.45 arcminutes. The cluster’s age is determined as 1.45 ± 0.10 Gyr, with a distance of 2220 ± 40 pc and a metallicity of [Fe/H] = −0.15 dex (z = 0.0109). We identify 4 centrally concentrated BSSs, and the total mass is estimated as 484 ± 22M ⊙. The apex motion is calculated as ( A o , D o ) = ( − 11 5 . ∘ 10 ± 0 . ∘ 09 , − 7 3 . ∘ 16 ± 0 . ∘ 12 ) . The orbital analysis of King 2 and King 5 indicates nearly circular orbits, characterized by low eccentricities and minimal variation in their apogalactic and perigalactic distances. King 2 and King 5 reach maximum heights of 499 ± 25 pc and 177 ± 2 pc from the Galactic plane, respectively, confirming their classification as young stellar disc population.

Context. Pismis 18 is a moderately populated, intermediate-age open cluster located within the solar circle at a Galactocentric distance of about seven kpc. Few open clusters have been studied in detail in the inner disc region before the Gaia-ESO Survey. Aims. New data from the Gaia-ESO Survey allowed us to conduct an extended radial velocity membership study as well as spectroscopic metallicity and detailed chemical abundance measurements for this cluster. Methods. Gaia-ESO Survey data for 142 potential members, lying on the upper main sequence and on the red clump, yielded radial velocity measurements, which, together with proper motion measurements from the Gaia Second Data Release (Gaia DR2), were used to determine the systemic velocity of the cluster and membership of individual stars. Photometry from Gaia DR2 was used to re-determine cluster parameters based on high confidence member stars only. Cluster abundance measurements of six radial-velocity member stars with UVES high-resolution spectroscopy are presented for 23 elements. Results. The average radial velocity of 26 high confidence members is −27.5 ± 2.5 (std) km s−1 with an average proper motion of pmra = −5.65 ± 0.08 (std) mas yr−1 and pmdec = −2.29 ± 0.11 (std) mas yr−1. According to the new estimates, based on high confidence members, Pismis 18 has an age of τ = 700+40−50 Myr, interstellar reddening of E(B − V) = 0.562+0.012−0.026 mag and a de-reddened distance modulus of DM0 = 11.96+0.10−0.24 mag. The median metallicity of the cluster (using the six UVES stars) is [Fe/H] = +0.23 ± 0.05 dex, with [α/Fe] = 0.07 ± 0.13 and a slight enhancement of s- and r-neutron-capture elements. Conclusions. With the present work, we fully characterized the open cluster Pismis 18. We confirmed its present location in the inner disc. We estimated a younger age than the previous literature values and we gave, for the first time, its metallicity and its detailed abundances. Its [α/Fe] and [s-process/Fe], both slightly super-solar, are in agreement with other inner-disc open clusters observed by the Gaia-ESO survey.

Using the photometric and kinematical data from Gaia Data Release 2, three old open clusters namely Berkeley 32 (Be 32), Berkeley 98 (Be 98), and King 23 are investigated. The latter two of these clusters are poorly studied in the literature. The numbers of the most probable cluster members are 563, 260, and 114 for Be 32, Be 98, and King 23, respectively, with membership probabilities higher than 80% and lying within the clusters’ limiting radii. Mean proper motions (PMs; and μ δ ) of the clusters are determined as (−0.34 ± 0.008, −1.60 ± 0.006), (−1.34 ± 0.007, −3.22 ± 0.008), and (−0.46 ± 0.009, −0.87 ± 0.012) mas yr−1. The errors mentioned in the PMs are the Gaussian fitting errors. The blue straggler stars (BSS) in all three old clusters were found to exhibit centralized radial distribution. The clusters’ radii are determined as 94, 1295, and 66 for Be 32, Be 98, and King 23 using radial density profiles. Ages of the clusters determined by isochrone fitting are 4.90 ± 0.22, 3.23 ± 0.15, and 1.95 ± 0.22 Gyr. The errors given in the clusters’ ages are the internal errors. The mass function slopes are found to be flatter than Salpeter’s value for all three clusters. All three clusters are found to be dynamically relaxed. Galactic orbits are derived for these clusters, which demonstrate that the studied clusters follow a circular path around the Galactic center.

Context. Open clusters are very good tracers of the evolution of the Galactic disc. Thanks to Gaia, their kinematics can be investigated with an unprecedented precision and accuracy. Aims. The distribution of open clusters in the 6D phase space is revisited with Gaia DR2. Methods. The weighted mean radial velocity of open clusters was determined, using the most probable members available from a previous astrometric investigation that also provided mean parallaxes and proper motions. Those parameters, all derived from Gaia DR2 only, were combined to provide the 6D phase-space information of 861 clusters. The velocity distribution of nearby clusters was investigated, as well as the spatial and velocity distributions of the whole sample as a function of age. A high-quality subsample was used to investigate some possible pairs and groups of clusters sharing the same Galactic position and velocity. Results. For the high-quality sample of 406 clusters, the median uncertainty of the weighted mean radial velocity is 0.5 km s−1. The accuracy, assessed by comparison to ground-based high-resolution spectroscopy, is better than 1 km s−1. Open clusters nicely follow the velocity distribution of field stars in the close solar neighbourhood as previously revealed by Gaia DR2. As expected, the vertical distribution of young clusters is very flat, but the novelty is the high precision to which this can be seen. The dispersion of vertical velocities of young clusters is at the level of 5 km s−1. Clusters older than 1 Gyr span distances to the Galactic plane of up to 1 kpc with a vertical velocity dispersion of 14 km s−1, typical of the thin disc. Five pairs of clusters and one group with five members might be physically related. Other binary candidates that have been identified previously are found to be chance alignments.

Context. Open clusters are very good tracers of the evolution of the Galactic disc. Thanks to Gaia, their kinematics can be investigated with an unprecedented precision and accuracy. Aims. The distribution of open clusters in the 6D phase space is revisited with Gaia DR2. Methods. The weighted mean radial velocity of open clusters was determined, using the most probable members available from a previous astrometric investigation that also provided mean parallaxes and proper motions. Those parameters, all derived from Gaia DR2 only, were combined to provide the 6D phase space information of 861 clusters. The velocity distribution of nearby clusters was investigated, as well as the spatial and velocity distributions of the whole sample as a function of age. A high quality subsample was used to investigate some possible pairs and groups of clusters sharing the same Galactic position and velocity. Results. For the high quality sample that has 406 clusters, the median uncertainty of the weighted mean radial velocity is 0.5 km/s. The accuracy, assessed by comparison to ground-based high resolution spectroscopy, is better than 1 km/s. Open clusters nicely follow the velocity distribution of field stars in the close Solar neighbourhood previously revealed by Gaia DR2. As expected, the vertical distribution of young clusters is very flat but the novelty is the high precision to which this can be seen. The dispersion of vertical velocities of young clusters is at the level of 5 km/s. Clusters older than 1 Gyr span distances to the Galactic plane up to 1 kpc with a vertical velocity dispersion of 14 km/s, typical of the thin disc. Five pairs of clusters and one group with five members are possibly physically related. Other binary candidates previously identified turn out to be chance alignment.

We analyze stellar proper motions in the COSMOS field to assess the presence of bulk motions. At bright magnitudes (G-band 18.5–20.76 AB), we use the proper motions of 1010 stars in the Gaia DR2 catalog. At the faint end, we compute proper motions of 11,519 pointlike objects at i-band magnitudes 19–25 AB using Hubble ACS and Subaru HSC data, which span two epochs about 11 yr apart. In order to measure these proper motions with unprecedented accuracy at faint magnitudes, we developed a foundational set of astrometric tools that will be required for joint survey processing of data from the next generation of optical/infrared surveys. The astrometric grids of Hubble ACS and Subaru HSC mosaics were corrected at the catalog level using proper motion–propagated and parallax-corrected Gaia DR2 sources. These astrometric corrections were verified using compact extragalactic sources. Upon comparison of our measured proper motions with Gaia DR2, we estimate the uncertainties in our measurements to be ∼2–3 mas yr−1 axis−1, down to 25.5 AB mag. We correct proper motions for the mean motion of the Sun, and we find that late-type main-sequence stars predominantly in the thin disk in the COSMOS field have space velocities mainly toward the Galactic center. We detect candidate high-velocity (≥220 km s−1) stars, six of them at ∼0.4–6 kpc, from the Gaia sample, and five of them at ∼20 kpc, from the faint star HSC and ACS sample. The sources from the faint star sample may be candidate halo members of the Sangarius stream.