James Webb Space Telescope Feed Post

Arxiv: A JWST Project on 47 Tucanae: Kinematics, energy equipartition and anisotropy of multiple populations Published: 2/5/2025 3:02:27 PM Updated: 2/5/2025 3:02:27 PM

Paper abstract: Recent work with JWST has demonstrated its capability to identify andchemically characterize multiple populations in globular clusters down to theH-burning limit. In this study, we explore the kinematics of multiplepopulations in the globular cluster 47 Tucanae by combining data from JWST,HST, and Gaia. We analyzed velocity dispersion and anisotropy profiles from thecluster center out to ~10R_h. Our findings indicate that while 1G starsare isotropic, 2G stars are significantly radially anisotropic. These resultsalign with the predictions of simulations of the dynamical evolution ofclusters where 2G stars are initially more centrally concentrated than 1Gstars. Furthermore, we subdivided the 2G population into two subpopulations:2G_A and 2G_B, with the latter being more chemically extreme. We comparedtheir dynamical profiles and found no significant differences. For the firsttime, we measured the degree of energy equipartition among the multiplepopulations of 47 Tucanae. Overall, within the analyzed radial range(~2-4R_h), both populations exhibit a low degree of energyequipartition. The most significant differences between 1G and 2G stars areobserved in the tangential velocity component, where 2G stars are characterizedby a stronger degree of energy equipartition than 1G stars. In the radialcomponent, the behavior of 1G and 2G stars is more variable, with differenceslargely dependent on radius. Finally, our analysis reveals that the ratio ofrotational velocity to velocity dispersion is larger for the 2G population,while 1G stars exhibit higher skewness in their tangential proper motions,providing further evidence of differences in the kinematic properties of the 1Gand 2G populations.