We conducted a homogeneous chemical analysis of pre-main sequence stars with effective temperatures ranging from ~3000K to ~5500K in eight nearby star-forming regions (SFRs): Chamaeleon I, eta Chamaeleonis, Lupus, Orion OB1a, Orion OB1b, sigma Orionis, Taurus, and Corona-Australis. Our study aims to: 1) derive the lithium abundance (A(Li)) and highlight the impact of veiling correction on both A(Li) and age determination; 2) perform the iron (Fe) and barium (Ba) abundance analysis in regions with scarce previous measurements; 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 of the lithium line (EWLi) at {lambda}=6707.8{AA}, from which A(Li) is 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 EWLi, which can shift A(Li) and age estimates by up to ~0.7dex and ~20Myr, respectively. Accounting for veiling, the A(Li) distributions peak in a range between 3.3 and 3.8dex for most clusters, and the upper age limit is approximately 5Myr for all SFRs. We successfully measured the mean iron and barium abundances in Lupus, Taurus, Cha I, and eta Cha, showing slightly sub-solar iron abundance, and a clear Ba overabundance, with [Ba/H] values reaching up to 0.75 dex.

Cone search capability for table J/A+A/709/A144/tablea1 (Results from the UVES spectra)

Cone search capability for table J/A+A/709/A144/tablea2 (Results from the ESPRESSO spectra)

Cone search capability for table J/A+A/709/A144/tablea3 (Results from the X-Shooter spectra)