SPIP at TBL, the faithfull companion of the SPIRou spectropolarimeter at CFHT : integration, tests and performances

Abstract

SPIP is a near infrared (nIR) echelle spectropolarimeter and a high-precision velocimeter for the 2-m Telescope Bernard Lyot (TBL – Pic du Midi, France), a twin version of SPIRou, mounted at the 3.6-m Canada France Hawaii Telescope (CFHT - Maunakea, Hawaii). This new generation instrument aims at detecting planetary worlds and Earth-like planets orbiting nearby red dwarfs, and at studying the impact of stellar magnetic fields on the formation of low-mass stars and their planets. The cryogenic spectrograph, cooled down at 70 K, is a fiber-fed double-pass cross-dispersed echelle spectrograph, covering the YJHK spectral bands (0.95-2.5 µm) in a single exposure. Among the key instrument parameters, high resolving power (of 70k) and long-term thermal stability (at a level better than 1 mK) are mandatory to achieve a relative radial velocity precision of 1-2 m/s. The engineering team at OMP / IRAP in Toulouse (France) took up the challenge of adapting and improving the SPIRou concept for SPIP to become the logical complement of SPIRou, to be used on the largest telescope in France for most of the available observing time. In this paper, we describe the work performed on the design, integration and in-lab tests on the assembled instrument in Toulouse. An evolved design on the Cassegrain unit, a completely new version of the spectrograph thermal insulation, as well as a number of minor upgrades with respect to SPIRou, should allow SPIP to be even more precise, stable and efficient than SPIRou