14 Herculis

14 Herculis is an orange dwarf star of the spectral type K0V. The star has about 98 percent of the mass, 97 percent of the radius, and only 67 percent of the luminosity of the Sun. The star appears to be 2.7 times as enriched with elements heavier than hydrogen (based on its abundance of iron), in comparison to the Sun.^[4] It may have been the most metal rich star known as of 2001.^[8]

In 1998 a planet, 14 Herculis b was discovered orbiting 14 Herculis via radial velocity.^[9][10] This was formally published in 2003.^[11] The planet has an eccentric orbit with a period of 4.8 years.^[12] In 2005, a possible second planet was proposed, designated 14 Herculis c.^[13] The parameters of this planet were very uncertain, but an initial analysis suggested that it was in the 4:1 resonance with the inner planet, with an orbital period of almost 19 years at an orbital distance of 6.9 AU.^[12] The existence of the planet 14 Herculis c was confirmed in 2021, along with a rough orbit determination.^[14]

A 2021 study combining radial velocity and astrometry found that the planetary orbits are not coplanar, which may indicate a strong planet-planet scattering event in the past.^[4] Subsequent astrometric studies have found differing results; a 2022 study found inclinations consistent with aligned orbits,^[15] while a 2023 study again found misaligned orbits.^[16] The latter study also found signs of a third candidate planet with a period of about 10 years, but this signal is most likely related to the star's magnetic activity cycle.^[16]

Direct imaging of the outer planet 14 Herculis c with the James Webb Space Telescope is planned.^[17]

• 47 Ursae Majoris
• List of stars in Hercules
• Lists of exoplanets