The NIRPS (Near-Infrared Planet Searcher) spectrograph is an instrument recently installed at the 3.6 m telescope in La Silla, Chile, operated by the European Southern Observatory (ESO). The concept for NIRPS is inspired by the SPIRou instrument. Indeed, NIRPS can, like SPIRou, detect and characterise exoplanets around low mass stars thanks to the velocimetry method, also known as the radial velocity method.
An important advantage of NIRPS is that it is installed at the same telescope as the HARPS (High Accuracy Radial velocity Planet Searcher) instrument. It is with this instrument, which observes in the visible spectrum, that it was possible to obtain radial velocity measurements with a precision better than 1 m/s (or 3.6 km/h) for the first time, which still represents an achievement in this field. The work carried out with HARPS has revolutionised our understanding of planetary systems in the vicinity of the Sun. NIRPS can be used in parallel with HARPS, which makes it possible to obtain data simultaneously in visible light and in the infrared. Teams using NIRPS thus have access to unique capabilities for monitoring and characterising exoplanets.
The majority of stars in the solar neighbourhood are low mass stars. We do not yet know all the planets they harbour. NIRPS is used to perform a systematic survey of the low-mass stars closest to the Sun and can detect Earth-like exoplanets in the habitable zone of these stars. These new discoveries will be prime candidates for direct imaging, and they could be among the first to be observed directly with future large telescopes, including the TMT and E-ELT. The discovery of an Earth-like planet in the habitable zone of our nearest neighbour, Proxima Centauri, bodes well for the discovery of many comparable planets.
NIRPS data can also be used to confirm and characterise exoplanets found by the transit method. Indeed, this method allows to identify planets and to find their radius and their orbital period, but not their mass. The radial velocity data from NIRPS will allow to obtain a mass measurement of planets identified by the TESS satellite, for example, in order to estimate their density and constrain their composition.
Following the success of SPIRou, the iREx obtained a grant from the Canada Foundation for Innovation to participate in the design and construction of NIRPS. The development of this instrument is part of a large international collaboration, which includes iREx, the Centre d’optique, photonique et laser of the Université Laval, the Geneva Observatory in Switzerland, the University of Grenoble in France, the Instituto de Astrofísica de Canarias in Spain, the NRC Herzberg Institute of Astrophysics in Canada, the University of Porto in Portugal, and the Universidade Federal do Rio Grande do Norte in Brazil.
Aware of the strategic importance of the NIRPS and HARPS duo, ESO has granted 740 nights of observation distributed over 5 years to the NIRPS team, of which several iREx researchers are a part. One of the two principal investigators of NIRPS is our Director, René Doyon. In addition, the Project Scientist is Étienne Artigau, one of the researchers working on the project is Jonathan St-Antoine, and the Project Manager is Lison Malo, assisted by Frédérique Baron. iREx researchers Neil Cook and Étienne Artigau are also involved in developing the instrument’s data reduction pipelines.