arXiv subjects

D. C. Çınar

Publications and source records attributed to D. C. Çınar.

5 recordsLinked to original sources

arXiv2026

Blue Straggler Stars in Berkeley 18: A Multiwavelength Study of Their Physical Properties and Dynamical Evolution

Berkeley~18 is an old open cluster in the outer Galactic disk that hosts a population of blue straggler stars (BSSs). We present a comprehensive multiwavelength analysis of its BSS population using \textit{Gaia} DR3 astrometry, optical--infrared photometry, and time-domain TESS observations. Using a Gaussian Mixture Model (GMM) in astrometric space, we identify 798 high-probability cluster members ($p > 0.7$). Isochrone fitting yields an age of $3.2 \pm 0.2$ Gyr and a heliocentric distance of $5.01^{+0.75}_{-0.55}$ kpc. We identify 24 BSS candidates above the main-sequence turn-off. Spectral energy distribution (SED) modelling reveals effective temperatures of $6000$--$8500$ K, radii of $1.4$--$5.7\,R_\odot$, and luminosities of $3.3$--$38\,L_\odot$, indicating a heterogeneous population spanning multiple evolutionary stages. The BSS population exhibits only a mild central concentration, with a low $A^{+}$ parameter and an extremely low stellar collision-rate proxy, implying weak mass segregation and an inefficient collisional channel. We find no significant photometric variability among the BSS candidates within TESS's sensitivity limits. Although WISE W3/W4 data initially suggested possible mid-infrared excesses, detailed image inspection and SPHEREx spectrophotometry indicate that these are caused by background contamination and blending, with no clear evidence of circumstellar dust. The structural parameters derived from King-profile fitting ($r_c = 6.91^{+0.91}_{-0.73}$ arcmin, $r_t = 13.23^{+0.44}_{-0.43}$ arcmin) indicate a dynamically evolved, low-density system. Together, these results suggest that dynamical interactions are inefficient in Berkeley~18 and that binary evolution is likely the dominant formation channel of BSSs.

astro-ph.SR↗

arXiv2026

Structure and Evolution of Multi-Cluster within Galactic Disc: Gaia DR3 Insights into Eight Open Clusters

In this study, we present a comprehensive analysis of the structural, astrophysical, and dynamical properties of eight open clusters: NGC 559, NGC 1817, NGC 2141, NGC 7245, Ruprecht 15, Ruprecht 137, Ruprecht 142, and Ruprecht 169, using precise astrometric and photometric data from Gaia Data Release 3. By fitting the King model to the radial density profiles, we determined the structural parameters of the clusters, including core and limiting radii, which were found to range from 3.07 to 16.21 arcmin and from 9.97 to 25.97 arcmin, respectively. Fundamental astrophysical parameters were derived by fitting PARSEC isochrones to the colour-magnitude diagrams. The results show that the clusters have logarithmic ages between 7.95 and 9.34, metallicities in the range 0.007 to 0.015, and heliocentric distances between 1640 and 5203 pc. The total stellar masses of the clusters were estimated to lie between 257 and 1916 solar masses. For most of the clusters, the mass function slopes are consistent with the Salpeter initial mass function. Our dynamical analysis indicates that all clusters, except Ruprecht 15, are dynamically relaxed. In addition, the spatial distribution and the bimodal structure observed in the radial density profile of NGC 7245 provide strong evidence that this object is a binary cluster candidate. Finally, kinematic analysis and orbit integrations demonstrate that all clusters exhibit dynamical properties fully consistent with membership in the Galactic thin disc.

astro-ph.GA↗

arXiv2026

Tracing the Galactic Disk with Gaia DR3: A Deep Study of Berkeley 17, 18, and 39 Open Star Clusters

We report a detailed investigation of three intermediate-to-old age open clusters, Berkeley 17, Berkeley 18, and Berkeley 39, utilizing precise astrometric and photometric data from Gaia DR3. Cluster membership was robustly determined through a probabilistic proper-motion analysis, yielding statistically significant samples of 600, 1042, and 907 stars, respectively. From the mean parallaxes of these members, we determine astrometric distances ranging from approximately 3.40 kpc for Berkeley 17 to 5.80 kpc for Berkeley 18. Isochrone fitting applied to the decontaminated color-magnitude diagrams constrains the cluster ages to 9.12 +/- 1.00 Gyr, 3.36 +/- 0.50 Gyr, and 5.10 +/- 0.50 Gyr, respectively. Interstellar reddening spans a wide range, from E(B-V) = 0.17 mag in Berkeley 39 to 0.58 mag in Berkeley 17. Structural parameters derived from King model fits to the radial density profiles, combined with mass function analyses, indicate that the clusters are dynamically relaxed systems with mass distributions broadly consistent with the canonical Salpeter slope. Our kinematic analysis reveals that Berkeley 17, Berkeley 18, and Berkeley 39 are part of the outer disk population.

astro-ph.GA↗

arXiv2025

Exploring the Structure and Evolution of Four Young Open Clusters Near the Galactic Mid-plane via Gaia DR3

We present a comprehensive analysis of four young open clusters, NGC 663, NGC 2301, NGC 2384, and NGC 7510, utilizing high-precision astrometric and photometric data from Gaia DR3. Cluster membership was determined using the UPMASK algorithm, resulting in probable member counts ranging from 337 to 1498 across the clusters. Bayesian MCMC isochrone fitting yielded cluster ages in the range $\log t \sim 7.0$ -$8.15$, with uncertainties of $\sim 0.11$-$0.18$. Reddening values ranged from $E(B-V)=0.093$ mag in NGC 2301 to $1.24$ mag in NGC 7510, consistent with their positions near the Galactic plane. The stellar mass function slopes ($α\approx 2.00$-$2.26$) closely match the Salpeter IMF, with total stellar masses spanning nearly an order of magnitude, from $\sim 486\,M_\odot$ in NGC 2301 to $\sim 3584\,M_\odot$ in NGC 663. Dynamical relaxation times indicate that only NGC 2301 ($τ\approx 10.00$) and NGC 2384b ($τ\approx 2.03$) are dynamically relaxed; the others remain dynamically evolving. Orbital integrations in the MWPotential2014 model reveal nearly circular Galactic orbits with very low eccentricities ($e \approx 0.003$-$0.014$) and small vertical distances ($Z_{\rm max} < 0.142$ kpc), confirming their confinement to the thin disk. SED and kinematic analysis show that NGC 2384a and NGC 2384b are separated by $\sim 0.55$ kpc, indicating an optical pair.

astro-ph.GA↗

arXiv2024

Deeply Comprehensive Astrometric, Photometric, and Kinematic Studies of the Three OCSN Open Clusters with Gaia DR3

In this study, we considered the optical wavelength of Gaia DR3 to analyze poorly studied three newly open star clusters namely OCSN 203, OCSN 213, and OCSN 244 clusters with ASTECA code. Here, we identified candidates of 227, 200, and 551 with highly probable ($P \geq 50\%$) members. Fitting King's profile within RDPs allows us to estimate inner stellar structures like core (0.190 $\le r_{\rm c}$ (pc) $\le$ 1.284) and the limiting (0.327 $\le r_{\rm cl}$ (pc) $\le 1.302$) radii. Constructing CMDs fitted with suitable log age (yr) between (log t; 6.52 - 7.05) and metallicities (Z; 0.01308-0.01413) isochrones. Therefore, the estimated photometric parameters with CMDs, reflect the heliocentric distances are 332 $\pm$ 18, 529 $\pm$ 23, and 506 $\pm$ 23 (pc) for OCSN 203, OCSN 213, and OCSN 244, respectively. Furthermore, the collective mass ($M_{\rm C}$) in solar mass units calculated with MLR as 67 $\pm$ 8.19, 91 $\pm$ 9.54, and 353 $\pm$ 18.79. Additionally, LF determined that the mean absolute magnitudes are 9.54 $\pm$ 3.09, 8.52 $\pm$ 2.92, and 7.60 $\pm$ 2.76 for these clusters, respectively. The overall mass function reflects the slopes ($α$) for Salpeter within the uncertainty are ($α_{OCSN203}$ = 2.41 $\pm$ 0.06), ($α_{OCSN213}$ = 2.13 $\pm$ 0.07), and ($α_{OCSN244}$ = 2.28 $\pm$ 0.07). The results of this study which employed a dynamical analysis over varying timescales indicate that OCSN 203 and OCSN 244 are clusters that have undergone significant relaxation, with a dynamical evolution parameter ($τ$) that is much greater than one. In contrast, OCSN 213 exhibits characteristics of a non-relaxed cluster. A kinematic analysis of these open clusters was carried out, encompassing aspects of their apex position ($A_o,D_o$) using the AD diagrams. At the end, we found that the three OCSN clusters are young stellar disc members using dynamic orbit parameters.

astro-ph.SR↗