GJ 1289 b
| Discovery | |
|---|---|
| Discovery site | Canada–France–Hawaii Telescope |
| Discovery date | 2024 |
| Orbital characteristics | |
| 111.74 days | |
| Physical characteristics | |
| Mass | 6.27 M🜨0.020 MJ |
GJ 1289 b is a sub-Neptuneexoplanet orbiting the red dwarfstarGJ 1289, located approximately 8.86 parsecs (≈29 light-years) from the Sun. It was discovered using radial-velocity measurements with the near-infraredspectropolarimeter SPIRou at the Canada–France–Hawaii Telescope over multiple years, revealing a minimum mass of 6.27 ± 1.25 Earth masses and a nearly circular orbit with a period of 111.74 days. The host star, an M4.5V fully convective red dwarf with a mass of 0.21 solar masses, exhibits a strong large-scale dipolarmagnetic field of 200–240 G and a rotation period of ~73.7 days, which is distinct from the planet's orbital period.[1]
The planet's orbital distance places it beyond the conventional habitable zone of its cool, low-luminosity host, though it may still have a temperate atmosphere, making it a target for further study. Its discovery is notable for demonstrating the detection of planets around fully convective M dwarfs, whose magnetic activity differs significantly from that of partly convective stars, and for showing that low-amplitude radial-velocity signals can be reliably extracted even in the presence of strong stellar magnetic fields.[2]
References
- ^Moutou, C.; Ould-Elhkim, M.; Donati, J.-F.; Charpentier, P.; Cadieux, C.; Delfosse, X.; Artigau, E.; Arnold, L.; Baruteau, C.; Carmona, A.; Cook, N. J.; Cortes Zuleta, P.; Doyon, R.; Hébrard, G.; the SLS consortium (2024-08-22). "Characterising planetary systems with SPIRou: Temperate sub-Neptune exoplanet orbiting the nearby fully convective star GJ 1289 and a candidate around GJ 3378". Astronomy & Astrophysics. 688: A196. arXiv:2406.10384. Bibcode:2024A&A...688A.196M. doi:10.1051/0004-6361/202450466. ISSN 0004-6361.
- ^Lehmann, L T; Donati, J-F; Fouqué, P; Moutou, C; Bellotti, S; Delfosse, X; Petit, P; Carmona, A; Morin, J; Vidotto, A A; the SLS consortium (2023-11-09). "SPIRou reveals unusually strong magnetic fields of slowly rotating M dwarfs". Monthly Notices of the Royal Astronomical Society. 527 (2): 4330–4352. doi:10.1093/mnras/stad3472. ISSN 0035-8711.
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