section_path: Exoplanets
section_name: Exoplanets
paragraph_text: Exoplanets
  
  A misalignment between host star rotation plane and orbital plane of the planet is called obliquity and is usually measured with the Rossiter-McLaughlin effect. Around 10% of exoplanets have a misalignment between 80 and 125°. About half of these are warm Neptune sized or super-Neptune sized planets. Examples of exoplanets with nearly polar orbits are GJ 3470b, TOI-858Bb, WASP-178b, HD 3167c+d, TOI-640b, MASCARA-1 b, and GJ 436b.
  
  One explanation describes the misalignment of a circumbinary disk that forms the planets. When the central binary merges into a single star, the disk and any planets that have formed remain in a polar orbit. A study has shown that circumbinary disks are aligned with binaries that have a short orbital period of less than 20 days. Circumbinary disks around binaries with an orbital period of more than 30 days showed a wide range of alignments, including polar disks. The other explanation describes how a Neptune-sized planet might get into a polar orbit at the end of the planet formation. This happens due to a resonance with a protoplanetary disk in a system with an additional outer planet.
  
  In April 2025 astronomers using ESO 's UVES instrument on the Very Large Telescope announced strong evidence for a circumbinary planet orbiting the brown dwarf pair 2M1510 AB. The planet is called 2M1510(AB)b, or just 2M1510b. The orbit of the planet is unusual as it is a polar orbit around a binary system, the first such case that was discovered. The discovery was made with the help of radial velocity measurements that showed retrograde apsidal precession of the brown dwarf pair, which could not be explained by the outer companion.