2025MNRAS.541.1390S


Query : 2025MNRAS.541.1390S

2025MNRAS.541.1390S - Mon. Not. R. Astron. Soc., 541, 1390-1402 (2025/August-1)

James Webb Space Telescope observations of the white dwarf cooling sequence of 47 Tucanæ.

SALARIS M., SCALCO M., BEDIN L. and CASSISI S.

Abstract (from CDS):

We present a study of the white dwarf (WD) cooling sequence of the globular cluster 47 Tucanæ (47 Tuc or NGC 104) using deep infrared observations with the JWST. By combining these data with ultradeep optical imaging from the Hubble Space Telescope (HST) taken ${\sim}12$ yr earlier, we derived precise proper motions (PMs) and isolated a clean sample of WD cluster members. We estimated the cluster's age by comparing the observed WD cooling sequence luminosity function (LF), derived from JWST photometry, with theoretical models, obtaining a value of $11.8 \pm 0.5$ Gyr, in agreement with main-sequence turn-off ages, and ages determined from the masses and radii of two eclipsing binaries in the cluster. The age determined from the infrared LF is consistent with the optical LF based on the HST photometry. However, small discrepancies exist between the shape of the observed and theoretical LFs. To investigate these differences, we tested the cooling times of WD models populating the bright part of the observed cooling sequence against a semi-empirical calibration from the literature, based on bright WDs in 47 Tuc, finding agreement within less than $2 \sigma$. A more detailed analysis of dynamical effects and the impact of multiple stellar populations on the WD mass distribution in the observed field will be essential for addressing this discrepancy in future studies.

Abstract Copyright: © 2025 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.

Journal keyword(s): white dwarfs - globular clusters: general - 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 4 GlC 16 23 35.22 -26 31 32.7           ~ 1978 0
5 NGC 6397 GlC 17 40 42.09 -53 40 27.6     5.17     ~ 2103 0
6 NGC 6752 GlC 19 10 52.11 -59 59 04.4           ~ 2121 0

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