arXiv subjects

Remziye Canbay

Publications and source records attributed to Remziye Canbay.

11 recordsLinked to original sources

arXiv2026

The Comprehensive Investigations of the NGC 7419 Open Cluster and the New Perspective on Mass Populations

We present a structural, kinematic, and photometric analysis of the young, red supergiant- and Be star-rich open cluster NGC 7419 using Gaia DR3 and 2MASS data. Using the HDBSCAN algorithm and conservative membership criteria, we identify 734 high-probability cluster members, separating the cluster from the dense Perseus Arm background. Isochrone fitting to the Gaia DR3 color-magnitude diagram, treating classical Be stars separately to account for their circumstellar excess, yields an age of 15 +/- 2 Myr, a distance of 3161 +/- 261 pc, a distance modulus of 12.50 +/- 0.08 mag, and a color excess E(GBP-GRP) = 2.58 +/- 0.06 mag. An independent 2MASS analysis gives a consistent distance modulus of 12.53 mag and E(J-Ks) = 0.99 mag. The Be stars show a prominent infrared excess in J-Ks, consistent with free-free and bound-free emission from circumstellar disks. We derive mean proper motions of -2.738 +/- 0.115 and -1.604 +/- 0.149 mas yr^-1 and a mean parallax of 0.288 +/- 0.062 mas, corresponding to a trigonometric distance of 3316 +/- 317 pc. The photometric distance is adopted as the primary estimate. A generalized King profile gives a core radius of 1.53 +/- 0.08 arcmin and a limiting radius of 8.16 +/- 1.1 arcmin. The stellar mass distribution is best described by a three-component Gaussian model, which we interpret as three distinct mass populations. Their coexistence and incomplete mixing are consistent with the young dynamical state of NGC 7419. Hierarchical formation provides a plausible framework for their origin.

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arXiv2026

Kings of the Milky Way: A Homogeneous Gaia DR3 Analysis of King Open Clusters and the Galactic Disc Metallicity Gradient

This study aims to establish an internally homogeneous set of structural, astrophysical, and kinematical parameters for King open clusters and to assess their role as tracers of the Galactic thin disc. We present a homogeneous structural, astrophysical, and kinematical analysis of 27 King open clusters using high-precision Gaia DR3 astrometry, photometry, and spectroscopy. Cluster reddenings, distances, metallicities, and ages are determined via a homogeneous Markov Chain Monte Carlo isochrone-fitting approach applied to Gaia colour-magnitude diagrams. The derived parameters span E(G_BP-G_RP) = 0.113-1.933 mag, metallicities of [Fe/H] = -0.40 to +0.28 dex, ages from 17 to 6166 Myr, and heliocentric distances between 739 and 6272 pc. A comparison between astrometric and isochrone-based distances yields a median parallax difference of $-13\mu$as, indicating a good level of internal consistency between the photometric and astrometric distance scales within the adopted homogeneous framework. The radial metallicity behaviour of the King clusters is also examined using three complementary Galactic distance definitions and compared with the metallicity-radius relations obtained independently from 164 spectroscopically analysed open clusters from the literature. The King-cluster gradients are close to $-0.060$ dex kpc$^{-1}$ and are broadly consistent with those of the external reference sample, indicating that the homogeneously analysed King clusters follow the negative metallicity-radius trend traced by the broader thin-disc open-cluster population. Flatter gradients are found for young clusters, suggesting more homogeneous chemical enrichment at recent epochs. When dynamical constraints are applied to reduce the effects of radial migration and orbital blurring, the inferred gradient remains close to $-0.059$ dex kpc$^{-1}$.

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arXiv2026

Chemo-dynamical Analysis of Eight UBC Open Clusters

We present a comprehensive chemo-dynamical analysis of eight open clusters selected from the UBC catalog using Gaia DR3 data. These clusters are located at heliocentric distances of ~2-5 kpc, probing regions of the Galactic disk beyond the solar neighborhood. Cluster membership is determined using the UPMASK algorithm, while structural parameters are derived from radial density profiles through King model fitting combined with MCMC sampling. Their structural parameters reveal diverse internal configurations, from diffuse to moderately concentrated systems. Fundamental astrophysical parameters (extinction, distance, metallicity, and age) are obtained via Bayesian isochrone fitting based on PARSEC models. The clusters span a wide age range (~20 Myr to ~5 Gyr) and show a broad metallicity distribution (-0.34 <= [Fe/H] (dex) <= +0.25). Orbital analysis based on backward integrations shows that all clusters follow nearly circular orbits (e ~ 0.03-0.09) with low vertical distances from the Galactic plane (Zmax < 0.4 kpc), confirming their membership in the Galactic thin disk and dynamically cold kinematics. Comparison between inferred traceback orbital radii and present-day guiding radii indicates modest radial displacements, with Delta R < 0.5 kpc for the UBC sample. These offsets are consistent with mild radial redistribution expected for young, dynamically cold open clusters rather than strong radial migration. The results suggest that radial migration should be considered when interpreting the present-day spatial and chemical distribution of these clusters, although the inferred migration amplitudes remain moderate. Our results demonstrate that relatively distant open clusters can be characterized with high precision using Gaia DR3 data and that mild radial redistribution should be considered when interpreting the present-day distribution of stellar populations in the Galactic disk.

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arXiv2026

Geomagnetic Storm Impacts On The Ionosphere Over T\"urkiye During Solar Cycle 25: Focusing On The May 2024 Storm

The interaction between solar activity and Earth's magnetosphere magnetosphere-ionosphere system often results in geomagnetic storms that disturb ionospheric electron density. In this study, we analyse the ionospheric response to selected geomagnetic storm events during the Solar Cycle 25, focusing on the mid latitude region of Earth, including Turkey. Hourly Kp and Dst indices obtained from the OMNI database are compared with global TEC maps provided by NASA CDDIS. Storm time anomalies include short term enhancements and irregularities in electron content, correlated with geomagnetic activity. Unlike equatorial regions, mid-latitude ionospheric responses exhibit distinct features such as Storm Enhanced Density (SED). These findings emphasize the importance of continuous space weather monitoring for navigation and communication systems.

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arXiv2026

Detailed Analysis of the NGC 2168 Cluster, Leveraging Gaia DR3

NGC 2168 (M35) serves as a fundamental benchmark for studying stellar evolution and dynamical environments at the transition between young and intermediate-age populations. We present a comprehensive analysis of the cluster's kinematic, structural, and astrophysical properties utilizing high-precision astrometry and photometry data from Gaia Data Release 3 (DR3), complemented by 2MASS data. A statistical membership assessment yields a clean sample of probable members (N ~ 1397), with mean proper motion components of mu_alpha cos(delta) = 2.278 +/- 0.006 mas/yr and mu_delta = -2.893 +/- 0.006 mas/yr, along with a mean trigonometric parallax of varpi = 1.154 +/- 0.052 mas. We derived the cluster's fundamental parameters via isochrone fitting, determining an age of 190 +/- 12 Myr, a metallicity of [M/H] = -0.048 dex, and a probabilistic distance of 840 +/- 54 pc. The radial density profile is well described by a generalized King model with beta = 1 (rc = 7.97', rcl = 36.69'), revealing the presence of a loosely bound, extended stellar halo. Furthermore, we detect a spatial elongation oriented perpendicular to the Galactic plane, likely a signature of vertical tidal heating or disk shocking. The mass function analysis exhibits a multimodal Gaussian structure, suggesting a complex dynamical formation history beyond a simple power-law distribution. Finally, orbital integration confirms NGC 2168 as a thin disk object with a maximum vertical excursion of ~171 pc, consistent with the observed vertical morphological deformation.

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arXiv2026

Gaia DR3 Analysis of Four Open Clusters Toward the Galactic Anticenter

This study provides a detailed examination of the structural, astrophysical, kinematic, and dynamical properties of the open clusters COIN-Gaia 24, Czernik 24, FSR 0893, and UBC 74, which are located in the direction opposite to the Galactic center. Astrometric, photometric, and spectroscopic data from the Gaia Data Release 3 catalog were used to ensure a precise characterization of cluster members and their physical properties. Membership determination was performed using the UPMASK algorithm applied to a five-dimensional parameter space, yielding 116, 179, 238, and 387 likely members for each cluster, respectively. Structural parameters were derived by fitting King profiles to the radial density distributions of high-probability members. Astrophysical parameters were estimated through Bayesian Markov Chain Monte Carlo isochrone fitting based on PARSEC evolutionary models, complemented by spectral energy distribution analysis using ARIADNE. The resulting extinctions, distances, metallicities, and ages indicate that these are moderately reddened, intermediate-age clusters located between 1 and 3.5 kpc from the Sun. Mean radial velocities combined with Galactic orbital integrations computed with galpy show that all four clusters follow nearly circular, low-eccentricity orbits typical of thin-disc populations. All four OCs have dynamical relaxation times of 22-98 Myr. However, their ages exceed these times by several factors, particularly in Czernik 24, indicating that they are dynamically evolved systems, even though the calculated T_E values represent lower limits. The results confirm that these OCs serve as reliable tracers of the chemical and dynamical evolution of the Galactic thin disc.

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arXiv2025

V570 Per: Characterization of a Benchmark Eclipsing Binary

This study presents a comprehensive analysis of the detached binary system V570\,Per through combined photometric, spectroscopic, and astrometric observations. By disentangling the composite spectra, precise fundamental parameters and detailed chemical abundances were determined for both stars. The primary component has a mass of $1.4569_{-0.0100}^{+0.0094}$ $M_{\odot}$, a radius of $1.543_{-0.009}^{+0.012}$ $R_{\odot}$, an effective temperature of $6556_{-26}^{+64}$ K, and a metallicity of $+0.18_{-0.01}^{+0.03}$ dex, while the secondary has a mass of $1.3579_{-0.0089}^{+0.0094}$ $M_{\odot}$, a radius of $1.377_{-0.015}^{+0.013}$ $R_{\odot}$, an effective temperature of $6468_{-21}^{+32}$ K, and a metallicity of $+0.15_{-0.01}^{+0.02}$ dex. The system is estimated to be $577_{-60}^{+60}$ Myr old with a synchronized orbit. The available O-C data imply a minimum mass of 0.57 $M_{\odot}$ or 0.11 $M_{\odot}$ for the third body, corresponding to eccentric and circular orbits, respectively. \texttt{MESA} evolutionary models indicate that the primary will fill its Roche lobe and begin mass transfer to the secondary in about 2.8 Gyr, whereas the secondary will reach the terminal-age main sequence in approximately 3.2 Gyr. The chemical composition of both stars shows remarkable consistency, confirming their common origin, except for calcium, which is significantly enhanced in the primary. Line measurements support this difference and are therefore interpreted as an intrinsic abundance variation rather than an artifact of the analysis. The overall solar-rich metallicity, combined with a relatively low $α$-element content, links V570\,Per to the Galactic thin-disk population. In addition, Galactic orbit analyses of open clusters in the solar neighborhood have revealed that the V570\,Per system may have originated from the Melotte 25 open cluster.

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arXiv2025

Close Binary Open Cluster Systems: A Gaia DR3 Perspective on Alessi 36 and Collinder 135

In this study, we examined the nearby open clusters (OCs) Alessi 36 and Collinder 135. Their spatial proximity was assessed using photometric and astrometric data from \textit{Gaia} DR3. Likely member stars were identified based on a membership probability threshold ($P \geq 0.5$), yielding 230 members for Alessi 36 and 342 members for Collinder 135. The mean proper-motion components ($μ_α\cosδ, μ_δ$) were determined as $(-9.681 \pm 0.072, 7.021 \pm 0.081)$ mas yr$^{-1}$ for Alessi 36 and $(-10.061 \pm 0.083, 6.256 \pm 0.095)$ mas yr$^{-1}$ for Collinder 135. The parallax-based distances ($d$) were found to be $278 \pm 7$ and $299 \pm 11$ pc, while their estimated ages ($t$) were $39 \pm 5$ and $36 \pm 5$ Myr for Alessi 36 and Collinder 135, respectively. The Galactic orbital analysis of Alessi 36 and Collinder 135 reveals nearly circular orbits with low eccentricities and minor fluctuations in their apogalactic and perigalactic distances. The maximum heights they attain above the Galactic plane are $0.035 \pm 0.001$ kpc for Alessi 36 and $0.074 \pm 0.003$ kpc for Collinder 135, supporting their classification as part of the young stellar disc population.

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arXiv2025

Comprehensive Analysis of Middle-Aged Open Cluster NGC 6793 in Vulpecula via Gaia DR3 Data

We conducted an in-depth analysis of NGC 6793 open cluster via Gaia DR3 data, including astrometric, spectroscopic, and photometric measurements. Selection of 147 stars, which show membership probabilities $P\geq0.5$ were classified as likely members. The mean trigonometric parallaxes and proper-motion components of the cluster were found to be $\varpi = 1.674 \pm0.045$ mas and ($μ_α\cos δ$,~$μ_δ$) =($3.814\pm0.031$,~$3.547\pm0.034$) mas yr$^{-1}$. Fundamental astrophysical parameters of NGC 6793 are derived simultaneously as $t$ = $650 \pm 50$ Myr, $μ$ = $9.508\pm0.070$ mag, and $E(G_{\rm BP}-G_{\rm RP})$ = $0.361 \pm 0.035$ mag. Additionally, the cluster's luminosity function analysis reveals the $G$-absolute magnitude limit of the most likely stars, indicating a well-defined stellar population. The total mass of the cluster, determined through the mass function (MF) and considering stars with membership probabilities $P \geq 0.5$, was estimated as 139 $\pm$ 12 $M/M_{\odot}$. The slope of the MF was found to be $Γ= 1.40 \pm 0.26$, a result consistent with the Salpeter value. The kinematic analyses present velocity ellipsoid parameters as well as the convergent point $(A_{\rm o},~D_{\rm o}) = \left(85^{\circ}.85 \pm 0^{\circ}.11,~3^{\circ}.12 \pm 0^{\circ}.57\right)$. Analyses have shown that it is moving in a box-shaped orbit beyond the Sun's galactic radius and belongs to the thin disk population of the Milky Way. The calculated relaxation time suggests that NGC 6793 has reached a dynamically relaxed state, where the dynamical evolution parameter $τ$ significantly exceeds one. These results highlight both the cluster's internal stability and its connection to the thin disc population.

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arXiv2024

The Fundamental Parameters and Evolutionary Status of V454 Aurigae

Eclipsing binary systems have a unique feature, which enables scientists to obtain precise fundamental star parameters, which opens to greater area of astrophysics studies. In this study, we have derived the fundamental parameters, the evolutionary status, and the birthplace of V454 Aur in the Galaxy by combining radial velocity, photometric, and spectral energy distribution data. We have updated ephemerides and period of V454 Aur as $2458850.80136_{-0.00001}^{\,+0.00001}$ and $27.0198177_{-0.0000003}^{\,+0.0000003}$, respectively. We obtain $1.173^{\,+0.016}_{-0.016}$ $M_\odot$ and $1.203^{\,+0.022}_{-0.026}$ $R_\odot$ for the primary component and $1.045^{\,+0.015}_{-0.014}$ $M_\odot$ and $0.993^{\,+0.034}_{-0.027}$ $R_\odot$ for the secondary component. The effective temperatures for the components are accurately determined via SED data as $6250^{\,+150}_{-150}$ K and $5966^{\,+109}_{-89}$ K for the primary component and the secondary component, respectively. The metallicity of the components is derived from evolutionary tracks, which implies slightly higher than Solar metallicity. According to analysis, the components of V454 Aur are on the main sequence. Our distance calculation for the system is, which is $65.07^{\,+2}_{-3}$ pc, in excellent agreement with \textit{Gaia} astrometric data, which is $65.07^{\,+0.09}_{-0.09}$ pc. The current age of the system is $1.19_{-0.09}^{\,+0.08}$ Gyr, and it will start to mass transfer between components in 5 Gyr from now on. Dynamical orbital analysis shows that V454 Aur follows a boxy pattern around the Galactic centre and is a member of the thin-disc component of the Galaxy. Considering the age and metallicity of this system, it was found to have formed just outside the Solar circle.

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arXiv2019

Vilnius Photometry and Gaia Astrometry of Melotte 105

Archival Vilnius CCD photometric observations are presented for the heavily reddened star cluster Melotte 105, resulting in colour-magnitude diagrams and spectral class estimates. There is considerable lack of agreement between studies for reddening, age, and distance for this cluster explaining why the archival data are being made available by this paper. The derived reddening E(B-V =0.34 +/- 0.04 mag and the distance V-M =12.9 +/- 0.3 mag directly from the Vilnius photometry. The Gaia Data Release 2 (DR2) and Vilnius photometric data of the cluster were used to estimate the structural parameters of the cluster, probability of stellar membership in the cluster, the distance modulus and the cluster age. Lack of $Y$ band observations prevented determination of metal abundance. The values of the colour excess and distance module are determined by two different methods (i.e., Q and Zero Age Main Sequence, or ZAMS, methods). A distance modulus of 12.85 +/- 0.07 mag was derived by ZAMS fitting, in good agreement with the above estimate. ZAMS fitting indicates a reddening of 0.403 +/- 0.02 mag, within two sigma of the estimate above. The cluster's metallicity and age are estimated to be 0.24 dex and 240 +/-25 Myr, respectively. The derived mass function is in good agreement with the Salpeter slope. The cluster space velocity components (U, V, W) were determined as (-3.90 +/- 3.34, -13.76 +/- 5.69, +3.45 +/- 0.41) km/s. Perigalactic and apogalactic distances were obtained as R_{p} = 6.85 and R_{a} = 7.44 kpc respectively. The maximum vertical distance from the Galactic plane was calculated as Z_{max} = 84 pc and the eccentricity of the orbit was determined as e = 0.042.

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