The CARMENES search for exoplanets around M dwarfs

Guaranteed time observations Data Release 1 (2016-2020)^★

¹ Institut de Ciències de l’Espai (ICE, CSIC), Campus UAB, c/ Can Magrans s/n, 08193 Bellaterra, Barcelona, Spain
e-mail: iribas@ice.cat
² Institut d’Estudis Espacials de Catalunya (IEEC), c/ Gran Capità 2–4, 08034 Barcelona, Spain
³ Institut für Astrophysik und Geophysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
⁴ Centro de Astrobiología (CAB), CSIC-INTA, Campus ESAC, Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
⁵ Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Königstuhl 12, 69117 Heidelberg, Germany
⁶ Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany
⁷ Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
⁸ Centro Astronómico Hispano en Andalucía (CAHA), Observatorio de Calar Alto, Sierra de los Filabres, 04550 Gérgal, Almería, Spain
⁹ Instituto de Astrofísica de Canarias (IAC), 38200 La Laguna, Tenerife, Spain
¹⁰ Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain
¹¹ Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
¹² Instituto Universitario de Ciencias y Tecnologías Espaciales de Asturias, c/ Independencia 13, 33004 Oviedo, Spain
¹³ Departamento de Física de la Tierra y Astrofísica and IPARCOS-UCM (Instituto de Física de Partículas y del Cosmos de la UCM), Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
¹⁴ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
¹⁵ Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
¹⁶ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
¹⁷ Isdefe, Beatriz de Bobadilla 3, 28040 Madrid, Spain
¹⁸ Centro de Astrobiología (CAB), CSIC-INTA, Carretera de Ajalvir km 4, E-28850 Torrejón de Ardoz, Madrid, Spain
¹⁹ Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721, USA
²⁰ Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
²¹ Centre for Exoplanets and Habitability and Department of Physics, University of Warwick, Coventry CV4 7AL, UK
²² School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
²³ Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA
²⁴ Dipartimento di Fisica, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca Scientifica 1, 00133, Rome, Italy
²⁵ INAF – Osservatorio Astrofísico di Torino, via Osservatorio 20, 10025 Pino Torinese, Italy
²⁶ Consejo Superior de Investigaciones Científicas, Serrano 117, 28006 Madrid, Spain
²⁷ Universitäts-Sternwarte,Ludwig-Maximilians-UniversitätMünchen, Scheinerstrasse 1, 81679 München, Germany
²⁸ Exzellenzcluster Origins, Boltzmannstrasse 2, 85748 Garching, Germany
²⁹ Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 West Brooks Street, Norman, OK 73019, USA
³⁰ Kimmel fellow, Helen Kimmel Center for Planetary Science, Weizmann Institute of Science, Rehovot, Israel
³¹ Leiden Observatory, Leiden University, Postbus 9513, 2300 RA Leiden, The Netherlands
³² Department of Astronomy/Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
³³ Centre for Earth Evolution and Dynamics, Department of Geo-sciences, Universitetet i Oslo, Sem Sælands vei 2b, 0315 Oslo, Norway
³⁴ INAF – Osservatorio Astronomico di Padova, Vicolo dell’ Osservatorio 5, 35122 Padova, Italy
³⁵ Department of Physics, Ariel University, Ariel 40700, Israel
³⁶ Departament of Astronomy, Sofijski universitet, Sv. Kliment Ohridski”, 5 James Bourchier Boulevard, 1164 Sofia, Bulgaria
³⁷ AstroLAB IRIS, Provinciaal Domein “De Palingbeek”, Verbrande-molenstraat 5, 8902 Zillebeke, Ieper, Belgium
³⁸ Vereniging Voor Sterrenkunde, Oude Bleken 12, 2400 Mol, Belgium
³⁹ Centre for Mathematical Plasma Astrophysics, Katholieke Uni-versiteit Leuven, Celestijnenlaan 200B, bus 2400, 3001 Leuven, Belgium
⁴⁰ Department of Astronomy, University of Science and Technology of China, Hefei 230026, PR China

Received: 4 September 2022
Accepted: 12 December 2022

Abstract

Context. The CARMENES instrument, installed at the 3.5 m telescope of the Calar Alto Observatory in Almería, Spain, was conceived to deliver high-accuracy radial velocity (RV) measurements with long-term stability to search for temperate rocky planets around a sample of nearby cool stars. Moreover, the broad wavelength coverage was designed to provide a range of stellar activity indicators to assess the nature of potential RV signals and to provide valuable spectral information to help characterise the stellar targets.

Aims. We describe the CARMENES guaranteed time observations (GTO), spanning from 2016 to 2020, during which 19 633 spectra for a sample of 362 targets were collected. We present the CARMENES Data Release 1 (DR1), which makes public all observations obtained during the GTO of the CARMENES survey.

Methods. The CARMENES survey target selection was aimed at minimising biases, and about 70% of all known M dwarfs within 10 pc and accessible from Calar Alto were included. The data were pipeline-processed, and high-level data products, including 18 642 precise RVs for 345 targets, were derived. Time series data of spectroscopic activity indicators were also obtained.

Results. We discuss the characteristics of the CARMENES data, the statistical properties of the stellar sample, and the spectroscopic measurements. We show examples of the use of CARMENES data and provide a contextual view of the exoplanet population revealed by the survey, including 33 new planets, 17 re-analysed planets, and 26 confirmed planets from transiting candidate follow-up. A subsample of 238 targets was used to derive updated planet occurrence rates, yielding an overall average of 1.44 ± 0.20 planets with 1 M_⊕ < M_pl sin i < 1000 M_⊕ and 1 day < P_orb < 1000 days per star, and indicating that nearly every M dwarf hosts at least one planet. All the DR1 raw data, pipeline-processed data, and high-level data products are publicly available online.

Conclusions. CARMENES data have proven very useful for identifying and measuring planetary companions. They are also suitable for a variety of additional applications, such as the determination of stellar fundamental and atmospheric properties, the characterisation of stellar activity, and the study of exoplanet atmospheres.