Berkeley 32: A Metal-poor and Dynamically Evolved Open Cluster with Evidence of Radial Migration
ASTRONOMICAL JOURNAL, cilt.172, sa.3, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 172 Sayı: 3
- Basım Tarihi: 2026
- Doi Numarası: 10.3847/1538-3881/ae8d05
- Dergi Adı: ASTRONOMICAL JOURNAL
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, INSPEC, Directory of Open Access Journals
- Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
- İstanbul Üniversitesi Adresli: Evet
Özet
We present a comprehensive chemodynamical analysis of the old, metal-poor open cluster Berkeley 32 based on Gaia DR3 astrometry and Gaia-ESO Survey DR5.1 spectroscopy. Cluster membership is determined using a Gaussian mixture model applied to proper-motion components and trigonometric parallaxes. Isochrone fitting yields an age of 4.9 +/- 0.5 Gyr, a heliocentric distance of 3325 pc, and an extinction of AV = 0.38 +/- 0.12 mag. Spectroscopic member stars exhibit a mean metallicity of [Fe/H] = -0.39 +/- 0.02 dex, near-solar alpha-element abundances, and a weighted mean radial velocity of Vrad = 106.26 +/- 0.03 km s-1. The [Y/Mg] chemical clock yields an age of 4.73 +/- 2.39 Gyr, consistent with the isochrone estimate. Orbital integration indicates a moderately eccentric orbit (e = 0.268 +/- 0.004) with a guiding radius of Rg = 8.82 kpc. The inferred chemical birth radius, Rb = 9.82 kpc, together with Delta R approximate to - 1 kpc, suggests moderate inward radial migration, while the offsets among Rb, Rg, and RGC are consistent with both churning and blurring processes. A photometric analysis identifies a binary fraction of fb = 0.449 +/- 0.017 for systems with mass ratios q >= 0.5, implying a substantial unresolved binary population. Radial cumulative distribution functions further reveal significant mass segregation, with evolved stars more centrally concentrated than main-sequence stars. These results indicate that Berkeley 32 is a dynamically evolved old-disk cluster whose present-day structure and orbit preserve signatures of both internal dynamical evolution and radial migration within the Galactic disk.