14 Herculis c

14 Herculis c
	Direct image of 14 Herculis c taken with the James Webb Space Telescope. Its host star is blocked by a coronagraph.
Discovery
Discovered by	Goździewski et al.; Rosenthal et al.
Discovery site	Observatoire de Haute-Provence, Keck & AFP
Discovery date	17 November 2005 (candidate); 2 July 2021 (confirmed)
Detection method	Doppler spectroscopy
Designations
Alternative names	HD 145675 c
Orbital characteristics
Semi-major axis	20.0+12.0; −4.9 AU; 28.1+6.4; −6.8 AU
Eccentricity	0.64+0.06; −0.10
Orbital period (sidereal)	52,160±1,030 days; (142.8±2.8 years)
Inclination	111.9°+5.4°; −5.5°
Longitude of ascending node	205.1°+7.448°; −10.31°
Time of periastron	2,451,779±33 JD
Argument of periastron	172.5°+4.011°; −4.584°
Semi-amplitude	50.8±0.4 m/s
Star	14 Herculis
Physical characteristics
Mean radius	1.03±0.01 RJ
Mass	7.9+1.6; −1.2 MJ
Surface gravity	4.25±0.15 cgs
Temperature	275 K (2 °C; 35 °F)

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),^[1] using data from the ELODIE Planet Search survey.^[3] It remained a planet candidate until its existence was securely confirmed in 2021.^[2]

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.^[7]

The inclination and true mass of 14 Herculis c were measured in 2021, using data from Gaia,^[8] and refined by further astrometric studies in 2022 and 2023,^[9]^[6] as well by a 2025 study using James Webb Space Telescope astrometry. The inclination is 116°, corresponding to a true mass of 7.1 M_J.^[6]

Direct imaging

The planet was directly imaged with the James Webb Space Telescope's NIRCam instrument in 2025. The observations determined a temperature of 275 K (2 °C), 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.^[10]^[4]

References

^ ^a ^b Goździewski, K.; Konacki, M.; Maciejewski, A. J. (2006). "Orbital Configurations and Dynamical Stability of Multiplanet Systems around Sun-like Stars HD 202206, 14 Herculis, HD 37124, and HD 108874" (PDF). The Astrophysical Journal. 645 (1): 688–703. arXiv:astro-ph/0511463. Bibcode:2006ApJ...645..688G. doi:10.1086/504030. S2CID 15012577.
^ ^a ^b ^c Rosenthal, Lee J.; Fulton, Benjamin J.; Hirsch, Lea A.; Isaacson, Howard T.; Howard, Andrew W.; Dedrick, Cayla M.; Sherstyuk, Ilya A.; Blunt, Sarah C.; Petigura, Erik A.; Knutson, Heather A.; Behmard, Aida; Chontos, Ashley; Crepp, Justin R.; Crossfield, Ian J. M.; Dalba, Paul A.; Fischer, Debra A.; Henry, Gregory W.; Kane, Stephen R.; Kosiarek, Molly; Marcy, Geoffrey W.; Rubenzahl, Ryan A.; Weiss, Lauren M.; Wright, Jason T. (2021), "The California Legacy Survey. I. A Catalog of 178 Planets from Precision Radial Velocity Monitoring of 719 Nearby Stars over Three Decades", The Astrophysical Journal Supplement Series, 255 (1): 8, arXiv:2105.11583, Bibcode:2021ApJS..255....8R, doi:10.3847/1538-4365/abe23c, S2CID 235186973
^ ^a ^b Naef, D.; Mayor, M.; Beuzit, J. L.; Perrier, C.; Queloz, D.; Sivan, J. P.; Udry, S. (January 2004). "The ELODIE survey for northern extra-solar planets. III. Three planetary candidates detected with ELODIE". Astronomy and Astrophysics. 414: 351–359. arXiv:astro-ph/0310261. Bibcode:2004A&A...414..351N. doi:10.1051/0004-6361:20034091. ISSN 0004-6361.
^ ^a ^b ^c ^d ^e ^f Bardalez Gagliuffi, Daniella; Balmer, William O.; et al. (June 2025). "JWST Coronagraphic Images of 14 Her c: a Cold Giant Planet in a Dynamically Hot, Multi-planet System". The Astrophysical Journal Letters. arXiv:2506.09201.
^ ^a ^b ^c Xiao, Guang-Yao; Feng, Fabo (2025). "Updated Mutual Inclination Measurement for 14 Her b and c". arXiv:2506.13580 [astro-ph.EP].
^ ^a ^b ^c ^d Benedict, G. F.; McArthur, B. E.; et al. (May 2023). "The 14 Her Planetary System: Companion Masses and Architecture from Radial Velocities and Astrometry". The Astronomical Journal. 166 (1): 27. arXiv:2305.11753. Bibcode:2023AJ....166...27B. doi:10.3847/1538-3881/acd93a.
^ Wittenmyer, R. A.; Endl, M.; Cochran, W. D. (2007). "Long-Period Objects in the Extrasolar Planetary Systems 47 Ursae Majoris and 14 Herculis". The Astrophysical Journal. 654 (1): 625–632. arXiv:astro-ph/0609117. Bibcode:2007ApJ...654..625W. doi:10.1086/509110. S2CID 14707902.
^ Bardalez Gagliuffi, Daniella C.; et al. (1 December 2021). "14 Her: A Likely Case of Planet–Planet Scattering". The Astrophysical Journal Letters. 922 (2). L43. arXiv:2111.06004. Bibcode:2021ApJ...922L..43B. doi:10.3847/2041-8213/ac382c.
^ Feng, Fabo; Butler, R. Paul; et al. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". The Astrophysical Journal Supplement Series. 262 (21): 21. arXiv:2208.12720. Bibcode:2022ApJS..262...21F. doi:10.3847/1538-4365/ac7e57. S2CID 251864022.
^ "Frigid Exoplanet in Strange Orbit Imaged by NASA's Webb". Webb. Retrieved 2025-06-10.

External links

Jean Schneider (2011). "Notes for Planet 14 Her c". Extrasolar Planets Encyclopaedia. Retrieved 30 September 2011.
"14 Herculis". SolStation. Archived from the original on 19 July 2008. Retrieved 2008-06-25.