2026A&A...707A..86Z


Query : 2026A&A...707A..86Z

2026A&A...707A..86Z - Astronomy and Astrophysics, volume 707A86 (2026/3-1)

A joint JWST and HST view of Omega Centauri: Multiple stellar populations and their kinematics.

ZILIOTTO T., MILONE A.P., CORDONI G., MARINO A.F., LEGNARDI M.V., DONDOGLIO E., BORTOLAN E. and MURATORE F.

Abstract (from CDS):

We combine F115W and F277W images collected with the Near Infrared Camera of the James Webb Space Telescope with multiband, multi-epoch Hubble Space Telescope observations of ω Centauri to investigate its multiple stellar populations and internal kinematics. Our study focuses on a region spanning ∼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 that are 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. However, metal-rich and metal-poor stars within each stream show moderate kinematic differences. The lower-stream stars show a higher angular momentum dispersion compared to upper-stream stars, and they also exhibit stronger systemic rotation and proper motion skewness, further highlighting their kinematic divergence. Finally, leveraging a mass range of ∼0.15-0.7 M⊙, we detected a low degree of energy equipartition for all cluster stars, which decreases with radial distance from the cluster center.

Abstract Copyright: © The Authors 2026

Journal keyword(s): techniques: photometric - astrometry - proper motions - globular clusters: individual: NGC 5139

VizieR on-line data: <Available at CDS (J/A+A/707/A86): photcat.dat chmlowms.dat chmupms.dat>

Status at CDS : Tables of objects will be appraised for possible ingestion in SIMBAD.

Simbad objects: 7

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Number of rows : 7
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 NGC 5139 GlC 13 26 47.28 -47 28 46.1           ~ 3677 0
3 NGC 5286 GlC 13 46 26.81 -51 22 27.3           ~ 485 0
4 M 22 GlC 18 36 23.94 -23 54 17.1           ~ 1459 0
5 M 54 GlC 18 55 03.33 -30 28 47.5           ~ 1164 0
6 NAME SDG G 18 55 19.0 -30 32 43   4.5 3.6     ~ 2438 2
7 M 2 GlC 21 33 27.02 -00 49 23.7     6.25     ~ 1114 1

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