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 σ-Orionis^⋆

¹ European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
e-mail: cmanara@eso.org
² INAF – Osservatorio Astrofisico di Catania, Via S. Sofia, 78, 95123 Catania, Italy
³ NASA Ames Research Center, Moffett Blvd, Mountain View, CA 94035, USA
⁴ Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network (ELKH), Konkoly-Thege Miklós út 15-17, 1121 Budapest, Hungary
⁵ Kavli Institute for Astronomy and Astrophysics, Peking University, Yiheyuan 5, Haidian Qu, 100871 Beijing, PR China
⁶ Department of Astronomy, University of Michigan, 1085 S. University Ave., Ann Arbor, MI 48109, USA
⁷ Instituto de Astronomía, UNAM, Campus Ensenada, Carretera Tijuana-Ensenada km 103, 22860 Ensenada, BC, Mexico
⁸ INAF – Osservatorio Astronomico di Roma, Via di Frascati 33, 00078 Monte Porzio Catone, Italy
⁹ INAF – Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy
¹⁰ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
¹¹ Cerro Tololo Inter-American Observatory/NSF’s NOIRLab, Casilla, 603 La Serena, Chile
¹² SUPA, School of Science and Engineering, University of Dundee, Nethergate, Dundee DD1 4HN, UK
¹³ School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2, Ireland
¹⁴ INAF – Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese, Italy
¹⁵ INAF – Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi, 5, 50125 Firenze, Italy
¹⁶ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
¹⁷ ELTE Eötvös Loránd University, Institute of Physics, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary
¹⁸ Department of Physics, Texas State University, 749 N Comanche Street, San Marcos, TX 78666, USA
¹⁹ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
²⁰ Observatoire de Paris, PSL University, Sorbonne University, CNRS, LERMA, 61 Av. de l’Observatoire, 75014 Paris, France
²¹ School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
²² Thüringer Landessternwarte, Sternwarte 5, 07778 Tautenburg, Germany
²³ Universität Sternwarte München, Ludwig-Maximillian-Universität, Scheinerstrasse 1, 81679 München, Germany
²⁴ Institute for Astrophysical Research, Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA
²⁵ Purple Mountain Observatory, Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, PR China
²⁶ Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309, USA
²⁷ Instituto de Astrofísica e Ciências do Espaço, CAUP & DFA/FCUP, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
²⁸ Sterrenkundig Instituut Anton Pannekoek, Science Park 904, 1098 XH Amsterdam, The Netherlands
²⁹ Crimean Astrophysical Observatory, 298409 Nauchny, Crimea
³⁰ MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
³¹ California Institute of Technology, 1200 East California Blvd, Pasadena, CA 91125, USA
³² European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
³³ Institute for Astronomy, University of Hawaii at Manoa, Honolulu, USA
³⁴ Dipartimento di Fisica, Universitá degli Studi di Milano, Via Giovanni Celoria 16, 20133 Milano, Italy
³⁵ Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Av. Gran Bretaña 1111, 5030 Casilla, Valparaíso, Chile
³⁶ Núcleo Milenio de Formación Planetaria – NPF, Universidad de Valparaíso, Av. Gran Bretaña 1111, Valparaíso, Chile
³⁷ Centro de Astrobiología (CSIC-INTA), Departamento de Astrofísica, ESA-ESAC Campus, PO Box 78 28691 Villanueva de la Cañada, Madrid, Spain
³⁸ School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
³⁹ INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
⁴⁰ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
⁴¹ School of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
⁴² Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany
⁴³ Eberhard-Karls Universität Tübingen, Sand 1, 72076 Tübingen, Germany
⁴⁴ INF – Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy
⁴⁵ Armagh Observatory and Planetarium, College Hill, Armagh BT61 9DG, UK
⁴⁶ Stony Brook University, Stony Brook, NY 11794, USA

Received: 23 February 2021
Accepted: 22 March 2021

Abstract

The evolution of young stars and disks is driven by the interplay of several processes, notably the accretion and ejection of material. These processes, critical to correctly describe the conditions of planet formation, are best probed spectroscopically. Between 2020 and 2022, about 500orbits of the Hubble Space Telescope (HST) are being devoted in to the ULLYSES public survey of about 70 low-mass (M_⋆ ≤ 2 M_⊙) young (age < 10 Myr) stars at UV wavelengths. Here, we present the PENELLOPE Large Program carried out with the ESO Very Large Telescope (VLT) with the aim of acquiring, contemporaneously to the HST, optical ESPRESSO/UVES high-resolution spectra for the purpose of investigating the kinematics of the emitting gas, along with UV-to-NIR X-shooter medium-resolution flux-calibrated spectra to provide the fundamental parameters that HST data alone cannot provide, such as extinction and stellar properties. The data obtained by PENELLOPE have no proprietary time and the fully reduced spectra are being made available to the whole community. Here, we describe the data and the first scientific analysis of the accretion properties for the sample of 13 targets located in the Orion OB1 association and in the σ-Orionis cluster, observed in November–December 2020. We find that the accretion rates are in line with those observed previously in similarly young star-forming regions, with a variability on a timescale of days (≲3). The comparison of the fits to the continuum excess emission obtained with a slab model on the X-shooter spectra and the HST/STIS spectra shows a shortcoming in the X-shooter estimates of ≲10%, which is well within the assumed uncertainty. Its origin can be either due to an erroneous UV extinction curve or to the simplicity of the modeling and, thus, this question will form the basis of the investigation undertaken over the course of the PENELLOPE program. The combined ULLYSES and PENELLOPE data will be key in attaining a better understanding of the accretion and ejection mechanisms in young stars.