Omega Cen JWST+HST phot. and proper motions

Our study focuses on a region spanning about 0.9 to 2.3 half-light radii from the cluster center, which is largely unexplored by these telescopes. Using chromosome maps, we identified the principal populations along the upper main sequence and among M dwarfs, distinguishing lower-stream stars chemically akin to first-generation globular cluster stars with similar metallicities from upper-stream stars enriched in helium and nitrogen but oxygen poor.

Both streams also host subpopulations with varying metallicities. We found radially anisotropic motions, with upper-stream stars exhibiting significantly stronger anisotropy than lower-stream stars. Subdividing the upper stream into extreme and intermediate light-element populations revealed a gradient in anisotropy, with intermediate stars lying between the lower-stream stars and extreme upper-stream populations.