Photometric, astrometric, and kinematical characteristics of two Xuyi's open clusters utilizing Gaia DR3 data

Abstract

This study reports and examines two poorly studied open star clusters surveyed from XSTPS-GAC, namely Xuyi 15 and Xuyi 23, using the Gaia DR3 catalog data. We identified 570 (Xuyi 15) and 824 (Xuyi 23) stars as highly probable astrometric members with membership probability higher than 60%. By fitting King's profile on radial density profiles (RDPs), we estimated both core and limiting radii and found rc about 1.95 ± 0.07 (Xuyi 15) and 4.55 ± 0.47 (Xuyi 23) while rlim are about 8.55 ± 2.92 (Xuyi 15) and 16.56 ± 4.07 (Xuyi 23) in pc units. We constructed CMDs for both clusters and calculated the fundamental parameters using the best-fitted isochrones of metallicity Z=0.03 and log age (yr) = 9.0 ± 0.05. The heliocentric distances are determined to be 7.413±0.90 kpc and 6.223±0.80 kpc for the clusters Xuyi 15 and Xuyi 23, respectively, using the isochrone fitting method. We have also obtained distances as 7.05-0.25+0.65 and 6.90-0.30+0.72 kpc for both clusters using the Bailer-Jones method. Moreover, total mass (MC;M⊙) was deduced with mass-luminosity relation (MLR) as 684 ± 26 and 1158 ± 34 and luminosity function (LF) concluded the absolute (MG; mag) of 4.05 ± 0.05 and 3.42 ± 0.04 for Xuyi 15 and Xuyi 23 clusters respectively. The overall mass function reflects the slopes (α) for Salpeter's value (2.35) within the uncertainty (i.e., αXuyi15 = 2.52 ± 0.06 and αXuyi23 = 2.34 ± 0.05). The present study and the dynamical analysis for different evolving times demonstrate that the clusters are dynamically relaxed, where the dynamical evolution parameter (τ) is much greater than one. Finally, we computed their coherent convergent points with AD-diagram method, thus (Ao,Do) are (99^o.27 ± 0^o.11, 20^o.91 ± 0^o.22; Xuyi 15) and (123^o.34 ± 0^o.09, -58o.27 ± 0^o.13; Xuyi 23).