14 Herculis c

Template:Short description 14 Herculis c or 14 Her c is the outermost of two known exoplanets orbiting the star 14 Herculis, approximately 58.4 light-years away in the constellation of Hercules. The planet has a mass that would make it a gas giant roughly the same size as Jupiter but much more massive.

Discovery

14 Herculis c was discovered by the radial velocity method. Its discovery was first reported in 2005 (published in 2006), using data from the ELODIE Planet Search survey. It remained a planet candidate until its existence was securely confirmed in 2021.

According to a 2007 analysis, the existence of a second planet in the 14 Herculis system was "clearly" supported by the evidence, but the planet's parameters were not precisely known. It may be in a 4:1 resonance with the inner planet 14 Herculis b.

The inclination and true mass of 14 Herculis c were measured in 2021, using data from Gaia, and refined by further astrometric studies in 2022 and 2023, as well by a 2025 study using James Webb Space Telescope astrometry. The inclination is 116°, corresponding to a true mass of Template:Jupiter mass.

Direct imaging

The planet was directly imaged with the James Webb Space Telescope's NIRCam instrument in 2025. The observations determined a temperature of , making it one of the coldest exoplanets directly imaged. They also re-measured its orbital elements, finding it to be closer to the star, at around 15 AU, on a highly eccentric orbit, as well as measuring its orbital inclination, finding it to be misaligned with 14 Herculis b by 40°. At wavelengths of 4.4 μm, its apparent magnitude is fainter than expected, hinting at disequilibrium chemistry and/or water ice clouds.

See also

• Epsilon Eridani b
• Epsilon Indi Ab
• HD 222237