Euclid: The convective-transition gap of 47 Tuc

arXiv:2606.28504 · astro-ph.SR, astro-ph.GA · Submitted 2026-06-26 · Read on arXiv

M. Libralato, M. Griggio, R. Gerasimov, L. R. Bedin, I. McDonald, B. Altieri, J. Anderson, F. Annibali, E. Balbinot, G. Battaglia, A. Bellini, P. Casenove, J. -C. Cuillandre, E. Dalessandro, A. M. N. Ferguson, H. R. A. Jones, K. Kuijken, F. Z. Majidi, D. Massari, A. Mohandasan, F. Niederhofer, G. Polenta, J. D. Sakowska, F. Soldano, C. Zerbinati, S. Andreon, N. Auricchio, H. Aussel, C. Baccigalupi, M. Baldi, A. Balestra, P. Battaglia, A. Biviano, E. Branchini, M. Brescia, S. Camera, V. Capobianco, C. Carbone, J. Carretero, M. Castellano, G. Castignani, S. Cavuoti, K. C. Chambers, A. Cimatti, C. Colodro-Conde, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, F. Courbin, H. M. Courtois, M. Cropper, H. Degaudenzi, G. De Lucia, H. Dole, F. Dubath, X. Dupac, M. Farina, R. Farinelli, F. Faustini, S. Ferriol, M. Frailis, E. Franceschi, S. Galeotta, K. George, B. Gillis, C. Giocoli, J. Gracia-Carpio, A. Grazian, F. Grupp, S. V. H. Haugan, H. Hoekstra, W. Holmes, I. M. Hook, F. Hormuth, A. Hornstrup, K. Jahnke, M. Jhabvala, S. Kermiche, A. Kiessling, B. Kubik, M. Kümmel, M. Kunz, H. Kurki-Suonio, A. M. C. Le Brun, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, O. Mansutti, O. Marggraf, M. Martinelli, N. Martinet, F. Marulli, R. J. Massey, E. Medinaceli, S. Mei, M. Meneghetti, E. Merlin, G. Meylan, A. Mora, L. Moscardini, R. Nakajima, R. C. Nichol, S. -M. Niemi, C. Padilla, S. Paltani, F. Pasian, W. J. Percival, V. Pettorino, M. Poncet, L. A. Popa, F. Raison, A. Renzi, J. Rhodes, G. Riccio, F. Rizzo, E. Romelli, M. Roncarelli, R. Saglia, Z. Sakr, D. Sapone, M. Schirmer, P. Schneider, T. Schrabback, A. Secroun, E. Sihvola, P. Simon, C. Sirignano, G. Sirri, L. Stanco, P. Tallada-Crespí, A. N. Taylor, I. Tereno, S. Toft, R. Toledo-Moreo, F. Torradeflot, I. Tutusaus, J. Valiviita, T. Vassallo, Y. Wang, J. Weller, D. Scott

INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy · Space Telescope Science Institute, 3700 San Martin Dr, Baltimore, MD 21218, USA · Department of Physics and Astronomy, University of Notre Dame, Nieuwland Science Hall, Notre Dame, 46556, Indiana, USA · INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy · Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK · ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Cañada, Madrid, Spain · Space Telescope Science Institute, 3700 San Martin Dr, Baltimore, MD 21218, USA · INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy · Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands · Universidad de La Laguna, Dpto. Astrofí sica, E-38206 La Laguna, Tenerife, Spain · Space Telescope Science Institute, 3700 San Martin Dr, Baltimore, MD 21218, USA · Centre National d'Etudes Spatiales -- Centre spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France · Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191, Gif-sur-Yvette, France · INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy · Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK · Department of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK · Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands · INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy · INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy · Universite Marie et Louis Pasteur, CNRS, Observatoire des Sciences de l'Univers THETA Franche-Comte Bourgogne, Institut UTINAM, Observatoire de Besançon, BP 1615, 25010 Besançon Cedex, France · Leibniz-Institut für Astrophysik · Space Science Data Center, Italian Space Agency, via del Politecnico snc, 00133 Roma, Italy · Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomí a, 18080, Granada, Spain · Institut d'Astrophysique de Paris, UMR 7095, CNRS, and Sorbonne Université, 98 bis boulevard Arago, 75014 Paris, France · INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy · INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy · INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy · Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191, Gif-sur-Yvette, France · SISSA, International School for Advanced Studies, Via Bonomea 265, 34136 Trieste TS, Italy · INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy · INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy · INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy · IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy · INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy · INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy · INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese · INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese · INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy · Port d'Informació Científica, Campus UAB, C. Albareda s/n, 08193 Bellaterra · INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy · INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy · INFN section of Naples, Via Cinthia 6, 80126, Napoli, Italy · Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA · Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Università di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy · Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife, Spain · Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK · Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK · ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Cañada, Madrid, Spain · Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France · Institut de Ciencies de l'Espai · UCB Lyon 1, CNRS/IN2P3, IUF, IP2I Lyon, 4 rue Enrico Fermi, 69622 Villeurbanne, France · Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK · Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland · INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy · Université Paris-Saclay, CNRS, Institut d'astrophysique spatiale, 91405, Orsay, France · Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland · ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Cañada, Madrid, Spain · INAF-Istituto di Astrofisica e Planetologia Spaziali, via del Fosso del Cavaliere, 100, 00100 Roma, Italy · INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy · INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy · Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France · INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy · INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy · INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy · University Observatory, LMU Faculty of Physics, Scheinerstr. 1, 81679 Munich, Germany · Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK · INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy · Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany · INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy · Universitäts-Sternwarte München, Fakultät für Physik, Ludwig-Maximilians-Universität München, Scheinerstr. 1, 81679 München, Germany · Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, 0315 Oslo, Norway · Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands · Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA · Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK · Felix Hormuth Engineering, Goethestr. 17, 69181 Leimen, Germany · Cosmic Dawn Center · Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany · NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA · Aix-Marseille Université, CNRS/IN2P3, CPPM, Marseille, France · Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA · Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France · Universitäts-Sternwarte München, Fakultät für Physik, Ludwig-Maximilians-Universität München, Scheinerstr. 1, 81679 München, Germany · Université de Genève, Département de Physique Théorique and Centre for Astroparticle Physics, 24 quai Ernest-Ansermet, CH-1211 Genève 4, Switzerland · Helsinki Institute of Physics, Gustaf Hällströmin katu 2, University of Helsinki, 00014 Helsinki, Finland · Laboratoire d'etude de l'Univers et des phenomenes eXtremes, Observatoire de Paris, Université PSL, Sorbonne Université, CNRS, 92190 Meudon, France · INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese · Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, 0315 Oslo, Norway · Helsinki Institute of Physics, Gustaf Hällströmin katu 2, University of Helsinki, 00014 Helsinki, Finland · SKAO, Jodrell Bank, Lower Withington, Macclesfield SK11 9FT, UK · INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy · Universität Bonn, Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany · INFN-Sezione di Roma, Piazzale Aldo Moro, 2 - c/o Dipartimento di Fisica, Edificio G. Marconi, 00185 Roma, Italy · Aix-Marseille Université, CNRS, CNES, LAM, Marseille, France · INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy · Department of Physics, Institute for Computational Cosmology, Durham University, South Road, Durham, DH1 3LE, UK · INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy · CNRS-UCB International Research Laboratory, Centre Pierre Binétruy, IRL2007, CPB-IN2P3, Berkeley, USA · INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy · INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy · Institute of Physics, Laboratory of Astrophysics, Ecole Polytechnique Fédérale de Lausanne · Telespazio UK S.L. for European Space Agency · INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy · Universität Bonn, Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany · School of Mathematics and Physics, University of Surrey, Guildford, Surrey, GU2 7XH, UK · European Space Agency/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands · Institut de Física d'Altes Energies · Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland · INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy · Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5, Canada · European Space Agency/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands · Centre National d'Etudes Spatiales -- Centre spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France · Institute of Space Science, Str. Atomistilor, nr. 409 Măgurele, Ilfov, 077125, Romania · Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany · INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy · Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA · INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy · INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy · INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy · INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy · Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany · Université St Joseph, Faculty of Sciences, Beirut, Lebanon · Departamento de Física, FCFM, Universidad de Chile, Blanco Encalada 2008, Santiago, Chile · Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany · Universität Bonn, Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany · Universität Innsbruck, Institut für Astro- und Teilchenphysik, Technikerstr. 25/8, 6020 Innsbruck, Austria · Aix-Marseille Université, CNRS/IN2P3, CPPM, Marseille, France · Department of Physics and Helsinki Institute of Physics, Gustaf Hällströmin katu 2, University of Helsinki, 00014 Helsinki, Finland · Universität Bonn, Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany · INFN-Padova, Via Marzolo 8, 35131 Padova, Italy · INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy · INFN-Padova, Via Marzolo 8, 35131 Padova, Italy · Port d'Informació Científica, Campus UAB, C. Albareda s/n, 08193 Bellaterra · Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK · Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências, Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal · Niels Bohr Institute, University of Copenhagen, Jagtvej 128, 2200 Copenhagen, Denmark · European University of Technology EUt+, European Union · Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas · Institut de Recherche en Astrophysique et Planétologie · Helsinki Institute of Physics, Gustaf Hällströmin katu 2, University of Helsinki, 00014 Helsinki, Finland · University Observatory, LMU Faculty of Physics, Scheinerstr. 1, 81679 Munich, Germany · Caltech/IPAC, 1200 E. California Blvd., Pasadena, CA 91125, USA · Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany · Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada

astro-ph.SR, astro-ph.GA

Submitted: 2026-06-26

Comments: 12 pages, 10 figures. Accepted for publication in A&A on 25 June 2026, first submission to A&A on 2 June 2026. Official Euclid data available at the CDS upon publication

License: http://creativecommons.org/licenses/by/4.0/

The gist: We report the first detection of the `convective-transition gap' (also known as `M-dwarf gap') in the globular cluster 47 Tuc (NGC 104) thanks to Euclid data.

Terminology

Abstract

We report the first detection of the `convective-transition gap' (also known as `M-dwarf gap') in the globular cluster 47 Tuc (NGC 104) thanks to Euclid data. 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 detect a statistically significant, sharp discontinuity in the main-sequence luminosity function of 47 Tuc at I E about 22.9, which we identify as the convective-transition gap. We compare the observed properties of the gap in 47 Tuc with theoretical models, showing how the gap can be a powerful diagnostic to probe 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 might be more general than previously thought. These results demonstrate that Euclid can be transformative well beyond cosmology, with impact across multiple areas of astrophysics, including resolved stellar populations.

Sources

Related papers