Year: 2026
Type: article
Abstract: We present strong evidence that mass segregation in the young open cluster NGC 2422 (age ≈84 Myr) is primarily driven by tidal stripping. Analysis of the radial mass distribution reveals a significant overabundance of low-mass stars ( M < 0.85 M ⊙ ) preferentially located near and beyond the cluster’s tidal radius ( r t = 14.4 pc), a hallmark of ongoing tidal stripping. This spatial signature is corroborated by kinematic evidence: the cluster’s outskirts exhibit an elevated velocity dispersion ( σ 3d = 14.9 km s −1 , F-test p < 0.001) and strong radial anisotropy ( β = 0.94 ±0.4), both classic signatures of tidal influence. The cluster’s age is significantly greater than its half-mass relaxation time ( t rh = 44.2 Myr), confirming it is dynamically evolved. Crucially, binary stars show no significant radial segregation from single stars (KS-test p ≈ 0.51), ruling them out as the primary driver. Collectively, these results establish tidal stripping as the dominant mechanism currently reshaping the structure and stellar content of NGC 2422.
Source: The Astronomical Journal
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W7128790434