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The evolution of young stars and disks is driven by the interplay of severalprocesses, notably accretion and ejection of material. Critical to correctlydescribe the conditions of planet formation, these processes are best probedspectroscopically. About five-hundred orbits of the Hubble Space Telescope(HST) are being devoted in 2020-2022 to the ULLYSES public survey of about 70low-mass (M<2Msun) young (age<10 Myr) stars at UV wavelengths. Here we presentthe PENELLOPE Large Program that is being carried out at the ESO Very LargeTelescope (VLT) to acquire, contemporaneous to HST, optical ESPRESSO/UVEShigh-resolution spectra to investigate the kinematics of the emitting gas, andUV-to-NIR X-Shooter medium-resolution flux-calibrated spectra to provide thefundamental parameters that HST data alone cannot provide, such as extinctionand stellar properties. The data obtained by PENELLOPE have no proprietarytime, and the fully reduced spectra are made available to the whole community.Here, we describe the data and the first scientific analysis of the accretionproperties for the sample of thirteen targets located in the Orion OB1association and in the sigma-Orionis cluster, observed in Nov-Dec 2020. We findthat the accretion rates are in line with those observed previously insimilarly young star-forming regions, with a variability on a timescale of daysof <3. The comparison of the fits to the continuum excess emission obtainedwith a slab model on the X-Shooter spectra and the HST/STIS spectra shows ashortcoming in the X-Shooter estimates of <10%, well within the assumeduncertainty. Its origin can be either a wrong UV extinction curve or due to thesimplicity of this modelling, and will be investigated in the course of thePENELLOPE program. The combined ULLYSES and PENELLOPE data will be key for abetter understanding of the accretion/ejection mechanisms in young stars.

astronomy and astrophysics

PENELLOPE: the ESO data legacy program to complement the Hubble UV  Legacy Library of Young Stars (ULLYSES) I. Survey presentation and accretion  properties of Orion OB1 and $\sigma$-Orionis