NIRPS joining HARPS at ESO 3.6 m. On-sky performance and science objectives
Abstract
The Near-InfraRed Planet Searcher (NIRPS) is a high-resolution, high-stability near-infrared (NIR) spectrograph equipped with an AO system. Installed on the ESO 3.6-m telescope, it was developed to enable radial velocity (RV) measurements of low-mass exoplanets around M dwarfs and to characterise exoplanet atmospheres in the NIR. This paper provides a comprehensive design overview and characterisation of the NIRPS instrument, reporting on its on-sky performance, and presenting its GTO programme. The instrument started its operations on 1 Apr 2023 after intensive on-sky testing phases. 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. The NIRPS AO-assisted fibre link improves coupling efficiency and offers a unique high-angular resolution capability with a fibre acceptance of only 0.4 arcsec. A high spectral resolving power of 90 000 and 75 000 is provided in HA and HE modes, respectively. The overall throughput from the top of the atmosphere to the detector peaks at 13 percent. The RV precision, measured on the bright star Proxima with a known exoplanetary system, is 77 cm/s. 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. 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 over several weeks. The instrument high throughput offers a notable improvement over previous spectrographs, enhancing our ability to detect small exoplanets.
Keywords
Cite
@article{arxiv.2507.21767,
title = {NIRPS joining HARPS at ESO 3.6 m. On-sky performance and science objectives},
author = {Francois Bouchy and Rene Doyon and Francesco Pepe and Claudio Melo and Etienne Artigau and Lison Malo and Francois Wildi and Frederique Baron and Xavier Delfosse and Jose Renan De Medeiros and Rafael Rebolo and Nuno C. Santos and Gregg Wade and Romain Allart and Khaled Al Moulla and Nicolas Blind and Charles Cadieux and Bruno L. Canto Martins and Neil J. Cook and Xavier Dumusque and Yolanda Frensch and Frederic Genest and Jonay I. Gonzalez Hernandez and Nolan Grieves and Gaspare Lo Curto and Christophe Lovis and Lucile Mignon and Louise D. Nielsen and Anne-Sophie Poulin-Girard and Jose Luis Rasilla and Vladimir Reshetov and Danuta Sosnowska and Michael Sordet and Jonathan Saint-Antoine and Alejandro Suarez Mascareno and Simon Thibault and Philippe Vallee and Thomas Vandal and Manuel Abreu and Jose L. A. Aguiar and Guillaume Allain and Tomy Arial and Hugues Auger and Susana C. C. Barros and Luc Bazinet and Bjorn Benneke and Xavier Bonfils and Anne Boucher and Vincent Bourrier and Sebastien Bovay and Christopher Broeg and Denis Brousseau and Vincent Bruniquel and Marta Bryan and Alexandre Cabral and Andres Carmona and Yann Carteret and Zalpha Challita and Bruno Chazelas and Ryan Cloutier and Joao Coelho and Marion Cointepas and Uriel Conod and Nicolas B. Cowan and Eduardo Cristo and Joao Gomes da Silva and Laurie Dauplaise and Antoine Darveau-Bernier and Roseane de Lima Gomes and Daniel Brito de Freitas and Elisa Delgado-Mena and Jean-Baptiste Delisle and David Ehrenreich and Joao Faria and Pedro Figueira and Dasaev O. Fontinele and Thierry Forveille and Jonathan Gagne and Ludovic Genolet and Felix Gracia Temich and Olivier Hernandez and Melissa J. Hobson and Jens Hoeijmakers and Norbert Hubin and Farbod Jahandar and Ray Jayawardhana and Hans-Ulrich Kauf and Dan Kerley and Johann Kolb and Vigneshwaran Krishnamurthy and David Lafreniere and Pierrot Lamontagne and Pierre Larue and Henry Leath and Alexandrine L Heureux and Izan de Castro Leao and Olivia Lim and Allan M. Martins and Jaymie Matthews and Jean-Sebastien Mayer and Yuri S. Messias and Stan Metchev and Leslie Moranta and Christoph Mordasini and Dany Mounzer and Nicola Nari and Ares Osborn and Mathieu Ouellet and Jon Otegi and Lena Parc and Luca Pasquini and Vera M. Passegger and Stefan Pelletier and Celine Peroux and Caroline Piaulet-Ghorayeb and Mykhaylo Plotnykov and Emanuela Pompei and Jason Rowe and Mirsad Sarajlic and Alex Segovia and Julia Seidel and Damien Segransan and Robin Schnell and Ana Rita Costa Silva and Avidaan Srivastava and Valentina Vaulato and Atanas K. Stefanov and Marcio A. Teixeira and Stephane Udry and Joost P. Wardenier and Bachar Wehbe and Drew Weisserman and Vincent Yariv and Gerard Zins},
journal= {arXiv preprint arXiv:2507.21767},
year = {2025}
}
Comments
26 pages, 32 figures, published in A&A, 2025, 700, A10