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Recent work withJWSThas demonstrated its capability to identify and chemically characterize multiple populations in globular clusters down to the H-burning limit. In this study, we explore the kinematics of multiple populations in the globular cluster 47 Tucanae by combining data fromJWST, HST, Gaia, and ground-based telescopes. We analyzed velocity dispersion and anisotropy profiles from the cluster center out to ∼10Rh. Our findings indicate that while first population (1G) stars’ motions are isotropic, second population (2G) stars’ motions are significantly radially anisotropic. These results align with the predictions of simulations of the dynamical evolution of clusters where 2G stars are initially more centrally concentrated than 1G stars. Furthermore, we subdivided the 2G population into two subpopulations: 2GAand 2GB, with the latter being more chemically extreme. We compared their dynamical profiles and found no significant differences. For the first time, we measured the degree of energy equipartition among the multiple populations of 47 Tucanae. Overall, within the analyzed radial range (∼2–4Rh), both populations exhibit a low degree of energy equipartition. The most significant differences between 1G and 2G stars are observed in the tangential velocity component, where 2G stars are characterized by a stronger degree of energy equipartition than 1G stars. In the radial component, the behavior of 1G and 2G stars is more variable, with differences largely dependent on radius. Moreover, our analysis reveals that the ratio of rotational velocity to velocity dispersion is larger for the 2G population. Finally, we found that 1G stars exhibit a higher skewness in their tangential proper motions than 2G stars, providing additional evidence of kinematic differences between the two stellar generations.
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The HST Large Programme on NGC 6752 ‐ V. Differences in luminosity and mass function among stellar populations
Abstract We exploit the astro‐photometric dataset of the multi‐epoch infrared parallel field of aHubble Space TelescopeLarge Programme aimed at studying the faintest stars of the globular cluster NGC 6752 to determine the luminosity and mass functions of the multiple stellar populations of this cluster. Thanks to the measurement of proper motions and deeper completeness, the results presented in this paper represent a significant improvement over those of previous studies. We successfully derived membership probabilities reaching stars as faint as , allowing us to reliably distinguish the three main stellar populations detected within this cluster. We employed a new set of model isochrones that have been individually fit to the colour–magnitude diagram of each population. We present a comprehensive analysis of the luminosity and mass functions for three stellar populations within NGC 6752. Notably, our findings reveal differences in the present‐day luminosity and mass functions of first‐generation and second‐generation stars; these differences are consistent with the manifestation of the effects of dynamical processes acting on populations with different initial spatial distributions. Finally, we publicly release the catalogues with positions, photometry, proper motions and memberships probabilities, as well as the stacked‐image atlases and all newly calculated stellar models.
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- Award ID(s):
- 2009193
- PAR ID:
- 10515420
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Astronomische Nachrichten
- Volume:
- 345
- Issue:
- 5
- ISSN:
- 0004-6337
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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