SPIP, a new instrument at the Pic du Midi de Bigorre to detect habitable exoplanets

A new comer has joined the quest for habitable worlds. At an altitude of 2,877 meters, at the summit of the Pic du Midi de Bigorre, the SPIP instrument has just been installed on the Bernard Lyot telescope. This technological marvel, the twin of the SPIRou instrument already in operation at the summit of Maunakea in Hawaii, places the Pic du Midi observation platform at the heart of international research into exoplanets and the formation of new worlds. This equipment will provide essential information for understanding our solar system, its history, its formation, and its evolution.

Supported by the CNRS, the University of Toulouse, and the Occitanie Region, SPIP (Pyrenean Infrared Spectropolarimeter) was designed by engineers and scientists at the OMP (IRAP, ATLAS) to address one of the major scientific challenges of the 21st century: detecting and characterizing rocky planets located around stars close to the Sun.

Thanks to its cutting-edge technology and extreme thermal stability, SPIP will be able to detect minute variations in the infrared light emitted by stars in order to diagnose the presence of potential rocky planets, explains Jean-François Donati, research director at the CNRS and scientific lead for the project at the Institute for Research in Astrophysics and Planetology (IRAP-OMP – CNES/CNRS/University of Toulouse). Red dwarf stars, which are smaller and cooler than the Sun, are our best candidates for finding habitable planets, and SPIP, like SPIRou, has been specially designed to observe them, he adds.

SPIP is not limited to hunting for exoplanets. As a spectropolarimeter capable of characterizing the vibrational modes of light, the instrument will also enable observation of stars in formation and the crucial role of magnetic fields in the genesis of new worlds. These observations will provide unprecedented insight into the very early stages of young stars’ lives, when, still surrounded by disks of gas and dust, they gradually shape their future planetary systems.

SPIP will also make it possible to detect and study giant gas planets around young stars, and even to study their atmospheres, thereby contributing to a better understanding of how worlds like Jupiter are formed. All of this data will shed light on the diversity of planetary systems and, by contrast, on the history of the solar system.

It took more than seven years of work by engineers and technicians from the Midi-Pyrénées Observatory Scientific Instrumentation Group (GIS OMP) and IRAP staff to design, manufacture, and assemble the more than 10,000 parts that make up this new scientific instrument. Operating at an extreme temperature of -200°C, stabilized to within a thousandth of a degree, this high-precision equipment required extraordinary logistics to be installed at the summit of the Pic du Midi de Bigorre, in conditions that were as demanding technically as they were humanly.

Transporting, integrating, and validating a high-precision cryogenic instrument in a high-altitude mountain environment required very specific skills and extremely detailed organization, confirms Marielle Lacombe, CNRS research engineer and SPIP project manager at GIS OMP. Four tons of precision equipment had to be transported to the summit, some of which was too large for the cable car and had to be transported by truck from the Col du Tourmalet and then by freight elevator to the telescope building.

Once the instrument has been adjusted and validated by an intensive program of laboratory and sky tests, scheduled for the first half of 2026, SPIP will work in synergy with its twin SPIRou in Hawai’i. This complementarity is essential: located on opposite sides of the Earth, SPIRou and SPIP will be able to observe common targets almost without interruption. This continuous coverage is crucial for scrutinizing the tiny variations in starlight and detecting their planets. By combining observations made with SPIP and SPIRou, astronomers will now be able to explore the diversity of extrasolar worlds in greater detail and accelerate the search for potentially habitable planets.

In the longer term, SPIP should contribute, alongside the JWST, PLATO, and ARIEL space telescopes, to some of the most eagerly awaited discoveries in astronomy: the identification of Earth-like planets and the study of their atmospheres.

More broadly, and beyond its support for cutting-edge scientific equipment, the Region, convinced of the importance of the research carried out at the Pic du Midi, is strengthening its support for the site and has also financed the expansion of the premises to accommodate researchers. All of these investments enable scientists working at the Pic du Midi to maintain and strengthen their level of excellence, while contributing to a better understanding of the challenges associated with climate change and supporting environmental transition, which are crucial issues for the future of our territories.

IRAP Contact

• Jean-François Donati, Jean-Francois.Donati@irap.omp.eu