PENELLOPE

IX. Lithium, iron, and barium elemental abundances in eight nearby young clusters

¹ INAF – Osservatorio Astronomico di Roma, via Frascati 33, 00078 Monte Porzio Catone (RM), Italy
² INAF – Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy
³ European Southern Observatory, Karl-Schwarzschild-Straße 2, 85748 Garching bei München, Germany
⁴ INAF – Osservatorio Astronomico di Capodimonte, via Moiariello 16, 80131 Napoli, Italy
⁵ Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences, MTA Centre of Excellence, Konkoly-Thege Miklós út 15–17, 1121 Budapest, Hungary
⁶ Institute of Physics and Astronomy, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary
⁷ Institute for Astronomy (IfA), University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria
⁸ Purple Mountain Observatory, Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, PR China
⁹ ASI, Italian Space Agency, Via del Politecnico snc, 00133 Rome, Italy
¹⁰ Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Ruadas Estrelas, 4150-762 Porto, Portugal
¹¹ Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Ruado Campo Alegre 687, 4169-007 Porto, Portugal
¹² Max-Planck-Insitut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
¹³ Instituto de Astronomía, Universidad Autónoma de México Ensenada, B.C., Mexico
¹⁴ Centro de Astrobiología (CAB), CSIC-INTA, Camino Bajo del Castillo s/n, 28692, Villanueva de la Cañada, Madrid, Spain
¹⁵ Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218, USA
¹⁶ Johns Hopkins University, Bloomberg Center for Physics and Astronomy, 3400 N. Charles Street, Baltimore, MD 21218, USA
¹⁷ Division of Physics and Astronomy, Alfred University, 1 Saxon Drive, Alfred, NY 14802, USA
¹⁸ Institut für Theoretische Physik und Astrophysik Christian-Albrechts-Universität zu Kiel, Leibnizstrasse 15, 24118 Kiel, Germany
¹⁹ Mt. Suhora Astronomical Observatory, University of the National Education Commission, ul. Podchorżych 2, 30-084 Kraków, Poland
²⁰ Thüringer Landessternwarte, Sternwarte 5, 07778 Tautenburg, Germany
²¹ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
²² SETI Institute, 339 Bernardo Ave., Suite 200, Mountain View, CA 94043, USA

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Received: 23 February 2026
Accepted: 24 March 2026

Abstract

We conducted a homogeneous chemical analysis of pre-main sequence stars with effective temperatures ranging from ∼3000 K to ∼5500 K in eight nearby star-forming regions (SFRs): Chamaeleon I, η Chamaeleonis, Lupus, Orion OB1a, Orion OB1b, σ Orionis, Taurus, and Corona-Australis. Our study aims to: (1) derive the lithium (Li) abundance (A(Li)) and highlight the impact of veiling correction on both the A(Li) and age determination; (2) perform an iron (Fe) and barium (Ba) abundance analysis in regions with scarce previous measurements; and (3) investigate the possible Ba enhancement. The analyzed data were obtained as part of the PENELLOPE Large Program using the ESPRESSO, UVES, and X-Shooter instruments. We measured the equivalent width (EW) of the Li line (EW_Li) at λ = 6707.8 Å, from which A(Li) was derived using the curves of growth method. The Fe and Ba abundances have been measured through spectral synthesis analysis. Using the EAGLES code, we derived an upper limit on the age of the eight SFRs. Our findings underscore the necessity of veiling corrections on EW_Li, which can shift A(Li) and age estimates by up to ∼0.7 dex and ∼20 Myr, respectively. When accounting for veiling, the A(Li) distributions peak in a range between 3.3 and 3.8 dex for most clusters and the upper age limit is approximately 5 Myr for all SFRs. We successfully measured the mean Fe and Ba abundances in Lupus, Taurus, Cha I, and η Cha, finding slightly subsolar Fe abundances and a clear Ba overabundance, with [Ba/H] values reaching up to 0.75 dex.