2025A&A...698A.209Z


Query : 2025A&A...698A.209Z

2025A&A...698A.209Z - Astronomy and Astrophysics, volume 698A209 (2025/6-1)

A JWST project on 47 Tucanae: Kinematics, energy equipartition, and anisotropy of multiple populations.

ZILIOTTO T., MILONE A.P., CORDONI G., AROS F.I., VESPERINI E., LEE J.-W., BELLINI A., BIANCHINI P., MASTROBUONO-BATTISTI A., LIBRALATO M., DONDOGLIO E., TAILO M., LIVERNOIS A., LEGNARDI M.V., LAGIOIA E., BORTOLAN E., MURATORE F., MARINO A.F., ALVES-BRITO A. and RENZINI A.

Abstract (from CDS):

Recent work with JWST has 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 from JWST, 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: 2GA and 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.

Abstract Copyright: © The Authors 2025

Journal keyword(s): techniques: photometric - astrometry - proper motions - globular clusters: individual: NGC 104

Simbad objects: 6

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Number of rows : 6
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026
#notes
1 NGC 104 GlC 00 24 05.359 -72 04 53.20     4.09     ~ 4158 0
2 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 12317 1
3 NGC 5139 GlC 13 26 47.28 -47 28 46.1           ~ 3677 0
4 M 5 GlC 15 18 33.22 +02 04 51.7     5.95     ~ 2095 0
5 M 92 GlC 17 17 07.39 +43 08 09.4     6.52     ~ 2240 0
6 NGC 6397 GlC 17 40 42.09 -53 40 27.6     5.17     ~ 2103 0

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