NIRPS joining HARPS at ESO 3.6 m
F. Bouchy, R. Doyon, F. Pepe, Claudio Melo, Étienne Artigau, Lison Malo, F. Wildi, Frédérique Baron, X. Delfosse, J. R. De Medeiros, R. Rébolo, N. C. Santos, Gregg Wade, Romain Allart, Khaled Al Moulla, Nicolas Blind, Charles Cadieux, Bruno L. Canto Martins, Jeremy Cook, X. Dumusque, Yolanda G. C. Frensch, Frédéric Genest, Jonay I. González Hernández, Nolan Grieves, G. Lo Curto, C. Lovis, L. Mignon, Louise D. Nielsen, Anne-Sophie Poulin-Girard, J. L. Rasilla, В. А. Решетов, D. Sosnowska, Michaël Sordet, Jonathan Saint-Antoine, Alejandro Su'arez Mascare no, Simon Thibault, P. Vallée, Thomas Vandal, Manuel Abreu, José L. A. Aguiar, Guillaume Allain, Tomy Arial, Hugues Auger, Susana C. C. Barros, Luc Bazinet, Björn Benneke, X. Bonfıls, Anne Boucher, V. Bourrier, Sébastien Bovay, C. Broeg, Denis Brousseau, Vincent Bruniquel, Marta L. Bryan, Alexandre Cabral, A. Carmona, Yann Carteret, Zalpha Challita, Bruno Chazelas, Ryan Cloutier, João M. P. Coelho, Marion Cointepas, Uriel Conod, Brooke Cowan, E. Cristo, João Gomes da Silva, Laurie Dauplaise, Antoine Darveau-Bernier, Roseane de Lima Gomes, D. B. de Freitas, E. Delgado Mena, J.-B. Delisle, D. Ehrenreich, Jo ao Faria, Pedro Figueira, O. Dasaev Fontinele, T. Forveille, Jonathan Gagné, Ludovic Genolet, Félix Gracia Témich, Olivier Hernandez, Melissa J. Hobson, H. J. Hoeijmakers, Norbert Hubin, Farbod Jahandar, Ray Jayawardhana, Hans-Ulrich Käufl, Dan Kerley, Johann Kolb, Vigneshwaran Krishnamurthy, D Lafrenière, Pierrot Lamontagne, P. Larue, Henry Leath, Alexandrine L’Heureux, Izan de Castro Leão, Olivia Lim, Allan M. Martins, J. M. Matthews, Jean-Sébastien Mayer
Abstract
Context . The Near-InfraRed Planet Searcher (NIRPS) is a high-resolution, high-stability near-infrared (NIR) spectrograph equipped with an adaptive optics (AO) system. Installed on the ESO 3.6-m telescope at La Silla Observatory, Chile, it was developed to enable radial velocity (RV) measurements of low-mass exoplanets around M dwarfs and to characterise exoplanet atmospheres in the NIR. Aims . This paper provides a comprehensive design overview and characterisation of the NIRPS instrument, reporting on its on-sky performance, advising on how to carry out observations, and presenting its guaranteed time observation (GTO) programme. Methods . Intensive on-sky testing phases were conducted between November 2019 and March 2023. The instrument started its operations on 1 April 2023. Results . The spectral range continuously covers the Y , J , and H bands from 972.4 to 1919.6 nm. The thermal control system maintains 1 mK stability over several months, thereby minimising drift. The NIRPS’s AO-assisted fibre link improves coupling efficiency and offers a unique high-angular resolution capability with a fibre acceptance of only 0.4″. A high spectral resolving power of R ~ 90 000 and R ~ 75 000 is provided in high-accuracy (HA) and high-efficiency (HE) modes, respectively. The overall throughput from the top of the atmosphere to the detector peaks at 13%. The RV precision, measured on the bright star Proxima with a known exoplanetary system, is 77 cms −1 . NIRPS and HARPS can be used simultaneously, offering unprecedented spectral coverage for spectroscopic characterisation and stellar activity mitigation. Modal noise can be aptly mitigated by the implementation of fibre stretchers and AO scanning mode. Conclusions . Initial results confirm that NIRPS opens new possibilities for RV measurements, stellar characterisation, and exoplanet atmosphere studies with high precision and high spectral fidelity. NIRPS demonstrated stable RV precision at the level of 1 m s −1 over several weeks. The instrument’s high throughput, particularly in the H band, offers a notable improvement over previous spectrographs, enhancing our ability to detect small exoplanets.