arXiv subjects

Özgün Arslan

Publications and source records attributed to Özgün Arslan.

3 recordsLinked to original sources

arXiv2025

Analysis of Newly Catalogued Open Star Cluster UPK~220 with Gaia DR3 and TESS: Discovering Member Variable Stars

Studies on star clusters with the same age and initial chemical composition have gained momentum in recent years with the use of \textit{Gaia}. In addition, the discovery of new clusters with Gaia has increased the number of open clusters to be examined. Many of these discovered sources are intermediate-age open clusters and have not been analyzed in detail yet. In this study, we focused on newly cataloged open cluster UPK~220. The fundamental parameters (distance, age, metallicity and reddening) of UPK~220 were determined by analysing the variable stars within the cluster, while simultaneously constraining the parameters of the variable stars using these cluster parameters. To achieve this, we combined GaiaDR3 and TESS photometric observations. Using GaiaDR3, we derive fundamental parameters of UPK~220 through membership analyses, and with TESS, we discovered eight member variable stars. We also extracted the atmospheric parameters ($logg$, $[Fe/H]$ and $T_{\rm eff}$) for the variable stars using SED, GSP-Phot and GSP-Spec, and MESA models.

astro-ph.SR↗

arXiv2022

The Cosmic-Ray Induced Sputtering Process On Icy Grains

In molecular cloud cores, the cosmic ray (CR) induced sputtering via CR ion-icy grain collision is one of the desorption processes for ice molecules from mantles around dust grains. The efficiency of this process depends on the incident CR ion properties as well as the physicochemical character of the ice mantle. Our main objective is the examination of the sputtering efficiency for H$_2$O and CO ices found in molecular cloud cores. In the calculation routine, we consider a multi-dimensional parameter space that consists of thirty CR ion types, five different CR ion energy flux distributions, two separate ice mantle components (pure H$_2$O and CO), three ice formation states, and two sputtering regimes (linear and quadratic). We find that the sputtering behavior of H$_2$O and CO ices is dominated by the quadratic regime rather than the linear regime, especially for CO sputtering. The sputtering rate coefficients for H$_2$O and CO ices show distinct variations with respect to the adopted CR ion energy flux as well as the grain size-dependent mantle depth. The maximum radius of the cylindrical latent region is quite sensitive to the effective electronic stopping power. The track radii for CO ice are much bigger than H$_2$O ice values. In contrast to the H$_2$O mantle, even relatively light CR ions ($Z \geq 4$) may lead to a track formation within the CO mantle, depending on ${\rm S_{\rm e,eff}}$. We suggest that the latent track formation threshold can be assumed as a separator between the linear and the quadratic regimes for sputtering.

astro-ph.EP↗

arXiv2014

Analytical Studies of NGC 2571, NGC 6802, Koposov 53 and Be 89

Astrophysical parameters (age, reddening, distance, radius, luminosity function, mass function, total mass, relaxation time and mass segregation) have been estimated for open clusters NGC 2571, NGC 6802, Koposov 53 and Be 89 by using the Two Micron All Sky Survey (2MASS) photometry. We analyse the color-magnitude diagrams and stellar radial density profiles. We have found that NGC 2571 is the youngest one having young main sequence stars while Be 89 is the oldest cluster.

astro-ph.GA↗