Euclid: The convective-transition gap of 47 Tuc

@article{libralato2026euclid,
  title = {{Euclid: The convective-transition gap of 47 Tuc}},
  author = {M Libralato and M Griggio and R Gerasimov and L.R Bedin and I Mcdonald and B Altieri and J Anderson and F Annibali and E Balbinot and G Battaglia and A Bellini and P Casenove and J.-C Cuillandre and E Dalessandro and A.M.N Ferguson and H.R.A Jones and K Kuijken and F.Z Majidi and D Massari and A Mohandasan and F Niederhofer and G Polenta and J.D Sakowska and F Soldano and C Zerbinati and S Andreon and N Auricchio and H Aussel and C Baccigalupi and M Baldi and A Balestra and P Battaglia and A Biviano and E Branchini and M Brescia and S Camera and V Capobianco and C Carbone and J Carretero and M Castellano and G Castignani and S Cavuoti and K.C Chambers and A Cimatti and C Colodro-Conde and G Congedo and C.J Conselice and L Conversi and Y Copin and F Courbin and H.M Courtois and M Cropper and H Degaudenzi and G de Lucia and H Dole and F Dubath and X Dupac and M Farina and R Farinelli and F Faustini},
  journal = {Astron.Astrophys.},
  year = {2026},
  month = sep,
  doi = {10.1051/0004-6361/202661247},
  eprint = {2606.28504},
  archivePrefix = {arXiv},
  url = {https://hal.science/hal-05743365v1},
  note = {CC BY},
}

TY  - JOUR
TI  - Euclid: The convective-transition gap of 47 Tuc
AU  - M Libralato
AU  - M Griggio
AU  - R Gerasimov
AU  - L.R Bedin
AU  - I Mcdonald
AU  - B Altieri
AU  - J Anderson
AU  - F Annibali
AU  - E Balbinot
AU  - G Battaglia
AU  - A Bellini
AU  - P Casenove
AU  - J.-C Cuillandre
AU  - E Dalessandro
AU  - A.M.N Ferguson
AU  - H.R.A Jones
AU  - K Kuijken
AU  - F.Z Majidi
AU  - D Massari
AU  - A Mohandasan
AU  - F Niederhofer
AU  - G Polenta
AU  - J.D Sakowska
AU  - F Soldano
AU  - C Zerbinati
AU  - S Andreon
AU  - N Auricchio
AU  - H Aussel
AU  - C Baccigalupi
AU  - M Baldi
AU  - A Balestra
AU  - P Battaglia
AU  - A Biviano
AU  - E Branchini
AU  - M Brescia
AU  - S Camera
AU  - V Capobianco
AU  - C Carbone
AU  - J Carretero
AU  - M Castellano
AU  - G Castignani
AU  - S Cavuoti
AU  - K.C Chambers
AU  - A Cimatti
AU  - C Colodro-Conde
AU  - G Congedo
AU  - C.J Conselice
AU  - L Conversi
AU  - Y Copin
AU  - F Courbin
AU  - H.M Courtois
AU  - M Cropper
AU  - H Degaudenzi
AU  - G de Lucia
AU  - H Dole
AU  - F Dubath
AU  - X Dupac
AU  - M Farina
AU  - R Farinelli
AU  - F Faustini
PY  - 2026
DA  - 2026/09/09
JO  - Astron.Astrophys.
DO  - 10.1051/0004-6361/202661247
UR  - https://hal.science/hal-05743365v1
AB  - We report the first detection of the ‘convective-transition gap’ (also known as the ‘M-dwarf gap’) in the globular cluster 47 Tuc (NGC 104). This feature, linked to a change in the physical properties of late-type dwarfs, has remained elusive, with only two detections so far. Leveraging the large number of stars, high resolution, and photometric precision enabled by Euclid , we detected a statistically significant, sharp discontinuity in the main-sequence luminosity function of 47 Tuc at I E ≈22.9, which we identify as the convective-transition gap. A comparison of the observed properties of the gap in 47 Tuc with theoretical models shows how the gap can be a powerful diagnostic for probing the internal chemical structure of globular clusters and their multiple stellar populations. Following its initial discovery in the metal-poor cluster NGC 6397, the identification of a convective gap in the metal-rich 47 Tuc suggests that this feature is more general than previously thought. These results demonstrate that Euclid can be transformative well beyond cosmology, with impacts across multiple areas of astrophysics, including resolved stellar populations.
ER  -