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arXiv · 2504.15341

Enhancing SED-Based Astrometric, Photometric, and Kinematic Studies of SAI 72 and SAI 75 Using Gaia DR3

Anwar Yousef Alzahrani·Aly Haroon·Waleed Elsanhoury·Deniz Cennet Çınar
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Abstract

This study investigates the open clusters SAI 72 and SAI 75 using Gaia DR3 data, employing the Automated Stellar Cluster Analysis (ASteCA) tool to determine their structural and fundamental properties, including center coordinates, size, age, distance, mass, luminosity, and kinematics. Based on membership probabilities (P >= 50%), we identified 112 and 115 stars as probable members of SAI 72 and SAI 75, respectively. Radial density profile (RDP) analysis yielded cluster radii of 2.35 arcmin for SAI 72 and 2.19 arcmin for SAI 75. The spectral energy distribution (SED) fitting was performed to refine metallicity, distance, and color excess parameters, ensuring consistency within 1 sigma of isochrone-based estimates. Isochrone fitting of the color-magnitude diagram (CMD) suggests ages of 316 Myr and 302 Myr, with corresponding distances of 3160 +/- 80 pc and 3200 +/- 200 pc. We derived their Galactic positions, projected distances (X_sun, Y_sun), and vertical displacements (Z_sun). Mass function analysis estimates cluster masses of 612 +/- 174 solar masses for SAI 72 and 465 +/- 90 solar masses for SAI 75. Kinematic studies indicate that both clusters have reached dynamical equilibrium. The AD diagram method provided convergent point coordinates of (A, D)_o = (97.016 +/- 0.09, 4.573 +/- 0.05) for SAI 72 and (99.677 +/- 0.10, 1.243 +/- 0.09) for SAI 75. Orbital analysis confirms that both clusters follow nearly circular trajectories with low eccentricities and minor variations in apogalactic and perigalactic distances. Furthermore, we determine that SAI 72 and SAI 75 originated beyond the solar circle at R_Birth = 10.825 +/- 0.068 kpc and R_Birth = 9.583 +/- 0.231 kpc, respectively. Their maximum heights above the Galactic plane, Z_max, are 109 +/- 9 pc for SAI 72 and 232 +/- 24 pc for SAI 75, reinforcing their classification as part of the young stellar disc population.

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Anwar Yousef Alzahrani, Aly Haroon, Waleed Elsanhoury, Deniz Cennet Çınar. 2025-04-21. Enhancing SED-Based Astrometric, Photometric, and Kinematic Studies of SAI 72 and SAI 75 Using Gaia DR3. https://arxiv.org/abs/2504.15341

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