14 Herculis b

Discovery

14 Herculis b was detected by measuring variations in its star's radial velocity as a result of the planet's gravity. This was done by making precise measurements of the Doppler shift of the spectrum of 14 Herculis. Prior to this analysis, another possible explanation of previous Doppler shift analysis included face-on spectroscopic binaries.

Orbit and mass

Preliminary astrometric measurements made by the Hipparcos satellite suggested that this planet has an orbital inclination of 155.3° with respect to plane of the sky, which would imply a true mass of 11.1 times that of Jupiter, close to the deuterium burning threshold that some astronomers use to define the distinction between a planet and a brown dwarf. However subsequent analysis suggests that the Hipparcos measurements were not precise enough to accurately determine the orbits. According to a 2008 paper, its inclination was being calculated via astrometry with Hubble, with publication expected by mid-2009.

The inclination and true mass of 14 Herculis b were finally measured in 2021, using data from Gaia, and refined by further astrometric studies in 2022, 2023, and 2024. The inclination is 147.3°, and the true mass is .

Direct imaging

Because of the wide separation between this planet and its host star, and the proximity of the 14 Herculis system to the Sun, it is a promising candidate for direct imaging of the planet, as the angular separation of the planet and host star will be large enough that the light from the planet and star might be spatially resolved. However, a search made using the adaptive optics CFHT 3.60m telescope on Mauna Kea did not make such a detection, confirming the object is not a star.

References

References

1. Mayor, M.. (1998). "Searching for giant planets at the Haute-Provence Observatory". ASP.
2. Pourbaix, D.. (2001). "Screening the Hipparcos-based astrometric orbits of sub-stellar objects". [[Astronomy and Astrophysics]].
3. (2008). "HST FGS astrometry - the value of fractional millisecond of arc precision".
4. "14 Herculis: A new extrasolar planet discovered at the Haute Provence Observatory".
5. (January 2003). "Seven New Keck Planets Orbiting G and K Dwarfs". [[The Astrophysical Journal]].
6. Dominique Naef. "Extrasolar Planetary Systems or Spectroscopic Binaries? Discrimination using Spectral Line Properties".
7. Wittenmyer, R. A.. (2007). "Long-Period Objects in the Extrasolar Planetary Systems 47 Ursae Majoris and 14 Herculis". [[The Astrophysical Journal]].
8. (1 December 2021). "14 Her: A Likely Case of Planet–Planet Scattering". The Astrophysical Journal Letters.
9. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". [[The Astrophysical Journal Supplement Series]].
10. (2025). "Updated Mutual Inclination Measurement for 14 Her b and C". Research Notes of the AAS.
11. (May 2023). "The 14 Her Planetary System: Companion Masses and Architecture from Radial Velocities and Astrometry". [[The Astronomical Journal]].
12. (2024-12-19). "Lessons learned from the detection of wide companions by radial velocity and astrometry". Monthly Notices of the Royal Astronomical Society.