SPIRou discovers new super-Earth neighboring our solar system
An international team led by researchers from the Institut de Recherche en Astrophysique et Planétologie (1) in Toulouse, the Institut de Planétologie et d’Astrophysique de Grenoble (2) , the Laboratoire d’Astrophysique de Marseille (3) and the Université de Montréal has discovered a new planet around the star Gl410, located 40 light-years from our Sun in the constellation Leo. The discovery was made using the SPIRou spectropolarimeter, installed on the Canada-France-Hawaiʻi telescope atop the Maunakea volcano, and the SOPHIE spectrograph at the Observatoire de Haute Provence.
The neighborhood of our solar system is dominated by small, cool stars, called red dwarfs. Their low luminosity makes it difficult to detect exoplanets orbiting these small stars. They also tend to have planets of more modest mass, making them harder to detect.
At least one new planet discovered
Through repeated visits over several years, the light of the star Gl410 has spoken: velocity measurements have revealed a periodic motion that is due to the presence of a planet with an orbital period of six days and ten times the mass of the Earth.
Based on the series of measurements, scientists then carry out statistical tests that reveal the degree of confidence they have in these discoveries. Detection is considered definitive above a given threshold, but may need to be confirmed by new observations. In the case of Gl410, two other planets would be present at 3 and 18.7 days orbital period, making the Gl410 system a compact, resonant set of small-mass planets.
What do we know about this planet?
Since the planet’s orbital period is six days, it receives 20 times more heat from its star than the Earth does from the Sun, and its equilibrium temperature could be around 300°C. The planet could resemble Neptune, only much hotter!
Scientists also know that this planet must be subject to strong and frequent eruptions from its star: red dwarfs are known to possess a very active magnetic field. Gl410, half as massive as the Sun, is a relatively young star (500 million years), and SPIRou measurements confirm a magnetic field 100 times more intense than that of our Sun. The consequences for planets could be the erosion of their atmosphere.
This new discovery illustrates, once again, the immense diversity of worlds and the infinite richness of their study. Discovering exoplanets is an intense team effort, from instrument design to operation and advanced data analysis. These discoveries have also been made possible by the incomparable sky quality at the summit of Maunakea volcano, where the Canada-France-Hawaiʻi telescope is installed, equipped with the SPIRou instrument. Maunakea is a mountain of cultural, natural and ecological importance and recognized as sacred by the native Hawaiians or Kānaka ʻŌiwi.
The observations were carried out as part of the SPIRou Legacy Survey, a Franco-Canadian program totalling over 300 nights over 3 years. They were combined with SOPHIE, obtained mainly between 2021 and 2023.
Notes
- (IRAP/OMP, CNRS, CNES, Université de Toulouse)
- (IPAG/OSUG, CNRS, Université Grenoble-Alpes)
- (LAM/Pythéas, CNRS, Aix-Marseille Université)
More information
About SPIRou
SPIRou, a spectrograph operating in the infrared spectral range from the Canada-France-Hawaiʻi Telescope, is more sensitive to starlight than ordinary optical instruments. It is at once a high-resolution spectral ladder spectrograph, a high-precision velocimeter and a spectropolarimeter operating in the infrared wavelengths. These features make it the ideal instrument for observing red dwarfs, and at the same time studying their processions of planets and the properties of their magnetic fields.
About SOPHIE
SOPHIE is the high-resolution spectrograph installed on the 193cm telescope at the Observatoire de Haute-Provence. It has been operating in the visible range with m/s precision for over 10 years. By observing the same star with both spectrographs, scientists can distinguish the signature of a planet from an effect due solely to the star.
IRAP Contact
- Claire Moutou, claire.moutou@irap.omp.eu
