---
OA_place: publisher
OA_type: diamond
_id: '18866'
abstract:
- lang: eng
text: Using JWST Near Infrared Camera (NIRCam) images of the globular cluster 47,Tucanæ,
(or NGC,104), taken at two epochs just 7 months apart, we derived proper-motion
membership down to F322W2 ∼ 27. We identified an intriguing feature at the very
low-mass end of the main sequence, around ∼ 0.08,M_⋅, at magnitudes F322W2 ∼ 24
and m_ F150W2 ∼ 25. This feature, dubbed 'kink', is characterized by a prominent
discontinuity in the slope of the main sequence. A similar discontinuity is seen
in theoretical isochrones with oxygen-poor chemistries, related to the rapid onset
of absorption. We therefore hypothesize that the cluster hosts disproportionately
more oxygen-poor stars near the bottom of the main sequence compared to the upper
main sequence and the red giant branch. Our results show no strong or conclusive
evidence of a rise in the brown dwarf luminosity function at faint magnitudes,
in contrast to previous findings likely affected by faint red background galaxies.
In our analysis, we accounted for this contamination by using proper motion membership.
acknowledgement: We dedicate this paper to the memory of our colleague Prof. Harvey
Richer (⋆ April 1944 —† 13 November 2023), a highly accomplished astronomer and
expert in stellar populations and in particular within globular clusters, who passed
away during this project. Harvey grew up in Montreal and was at least the second
star man to graduate from his high school, having been preceded by William Shatner
by more than a decade. He worked at the University of British Columbia for most
of his career, and his focus was the late stages of stellar evolution, in particular
carbon stars and white dwarfs. We thank the referee for his valuable suggestions
and comments, which helped improve the paper, as well as for his prompt revision.
article_number: A68
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: M.
full_name: Scalco, M.
last_name: Scalco
- first_name: R.
full_name: Gerasimov, R.
last_name: Gerasimov
- first_name: L. R.
full_name: Bedin, L. R.
last_name: Bedin
- first_name: E.
full_name: Vesperini, E.
last_name: Vesperini
- first_name: M.
full_name: Correnti, M.
last_name: Correnti
- first_name: D.
full_name: Nardiello, D.
last_name: Nardiello
- first_name: A.
full_name: Burgasser, A.
last_name: Burgasser
- first_name: H.
full_name: Richer, H.
last_name: Richer
- first_name: Ilaria
full_name: Caiazzo, Ilaria
id: 8ae5b6e7-2a03-11ee-914d-b58ed7a3b47d
last_name: Caiazzo
orcid: 0000-0002-4770-5388
- first_name: J.
full_name: Heyl, J.
last_name: Heyl
- first_name: M.
full_name: Libralato, M.
last_name: Libralato
- first_name: J.
full_name: Anderson, J.
last_name: Anderson
- first_name: M.
full_name: Griggio, M.
last_name: Griggio
citation:
ama: Scalco M, Gerasimov R, Bedin LR, et al. JWST photometry and astrometry of 47
Tucanae. Discontinuity in the stellar sequence at the star--brown dwarf transition.
Astronomy & Astrophysics. 2025;694. doi:10.1051/0004-6361/202452907
apa: Scalco, M., Gerasimov, R., Bedin, L. R., Vesperini, E., Correnti, M., Nardiello,
D., … Griggio, M. (2025). JWST photometry and astrometry of 47 Tucanae. Discontinuity
in the stellar sequence at the star--brown dwarf transition. Astronomy &
Astrophysics. EDP Sciences. https://doi.org/10.1051/0004-6361/202452907
chicago: Scalco, M., R. Gerasimov, L. R. Bedin, E. Vesperini, M. Correnti, D. Nardiello,
A. Burgasser, et al. “JWST Photometry and Astrometry of 47 Tucanae. Discontinuity
in the Stellar Sequence at the Star--Brown Dwarf Transition.” Astronomy &
Astrophysics. EDP Sciences, 2025. https://doi.org/10.1051/0004-6361/202452907.
ieee: M. Scalco et al., “JWST photometry and astrometry of 47 Tucanae. Discontinuity
in the stellar sequence at the star--brown dwarf transition,” Astronomy &
Astrophysics, vol. 694. EDP Sciences, 2025.
ista: Scalco M, Gerasimov R, Bedin LR, Vesperini E, Correnti M, Nardiello D, Burgasser
A, Richer H, Caiazzo I, Heyl J, Libralato M, Anderson J, Griggio M. 2025. JWST
photometry and astrometry of 47 Tucanae. Discontinuity in the stellar sequence
at the star--brown dwarf transition. Astronomy & Astrophysics. 694, A68.
mla: Scalco, M., et al. “JWST Photometry and Astrometry of 47 Tucanae. Discontinuity
in the Stellar Sequence at the Star--Brown Dwarf Transition.” Astronomy &
Astrophysics, vol. 694, A68, EDP Sciences, 2025, doi:10.1051/0004-6361/202452907.
short: M. Scalco, R. Gerasimov, L.R. Bedin, E. Vesperini, M. Correnti, D. Nardiello,
A. Burgasser, H. Richer, I. Caiazzo, J. Heyl, M. Libralato, J. Anderson, M. Griggio,
Astronomy & Astrophysics 694 (2025).
date_created: 2025-01-21T15:29:36Z
date_published: 2025-02-04T00:00:00Z
date_updated: 2025-07-10T11:51:28Z
day: '04'
ddc:
- '520'
department:
- _id: IlCa
doi: 10.1051/0004-6361/202452907
external_id:
arxiv:
- '2501.04446'
isi:
- '001414753300007'
file:
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creator: dernst
date_created: 2025-04-16T07:13:31Z
date_updated: 2025-04-16T07:13:31Z
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file_name: 2025_AstronomyAstrophysics_Scalco.pdf
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has_accepted_license: '1'
intvolume: ' 694'
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language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
publication: Astronomy & Astrophysics
publication_identifier:
eissn:
- 1432-0746
issn:
- 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: JWST photometry and astrometry of 47 Tucanae. Discontinuity in the stellar
sequence at the star--brown dwarf transition
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
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...