Direct imaging of 14 Herculis c by the James Webb Space Telescope.

The planet 14 Herculis c was discovered by the ELODIE Planet Search Survey in 2005, using the radial velocity method, which it was detected by the gravitational effect it has on its host star, 14 Herculis A, as these cause the star to wobble slightly on its axis. 14 Herculis is the outermost of two known planets in the 14 Herculis system, the other being 14 Herculis b. The star 14 Herculis A is a K-type orange dwarf star, slightly smaller than the Sun, 58.4 light years from our Solar System in the constellation of Hercules. The planet 14 Herculis c orbits this star at about 20 AU (i.e. about 20 times the average distance between the Earth and the Sun), with a orbital period of 152.8 years. It is estimated to be about the same size as Jupiter, but much more massive. This is due to the distance at which it orbits its star, which makes it much cooler than Jupiter, making the gasses from which it is made more dense.

Although several subsequent studies have confirmed the existence of 14 Herculis c, the planet had never been directly imaged. This changed in 2025, when the James Webb Space Telescope's Near Infrared Camera was trained upon the 14 Herculis system. The Webb study also enabled the direct measurement of the planet's temperature for the first time, showing that it's average surface temperature may be around -3°C.

14 Herculis c. The view is mostly black, with very faint red splotches in the central region of the image. At the center of the image, there is a black circle, and in the center of that, there is a star symbol representing a real star. This black circle blocks the light from the host star. To the lower right of the circle is a fuzzy bright orange circle, which is the exoplanet. NASA/ESA/CSA/STScl/William Balmer/Daniella Bardalez Gagliuffi.

14 Herculis c was imaged at 4.44 microns, an infrared wavelength equivalent to a temperature of -3°C. Although this was the predicted temperature for the exoplanet, it was found to be much dimmer than expected. This is theorized to indicate a much more active atmosphere than predicted, with warmer gas molecules from the planet's interior being brought to the surface rapidly due to internal churning.

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