14 Herculis

14 Herculis (Gliese 614) is a star somewhat less massive than our Sun (its mass is only 80% that of our Sun) and lies at a distance of 60 light-years as derived from the very precise HIPPARCOS astrometric satellite parallax. We have carefully measured 14 Herculis since 1994 at the Haute-Provence Observatory. These measurements have been done with the ELODIE spectrograph mounted on the 1.93 meter telescope. This summer, after more than four years of monitoring, the planet has completed its revolution around 14 Herculis. This planet has a slightly elongated orbit of 4.4 years. Its mass is about 3.3 times that of Jupiter and it is at a distance of 2.5 AU (1 AU is the Earth-Sun distance) from 14 Her.

This is the planetary orbit with the longest period among the presently discovered extrasolar planets. Nevertheless, this giant planet is still twice as close to 14 Her as Jupiter is to our Sun.

This long-period planet, orbiting a nearby star, is a very promising candidate for direct imaging. The longer the period, the larger the separation between the planet and the parent star, therefore the easier it becomes to distinguish the feeble glow of the planet near the bright glare of the star. The predicted separation between the planet and 14 Her is 0.14 arcsec, sufficient to make us try its detection with the adaptive optics system of the CFHT 3.60m at the summit of Mauna Kea in Hawaii. Despite the high quality of the images obtained no companion could be detected: we are not dealing with a star or a brown dwarf orbiting in a plane almost perpendicular to the line-of-sight, but with a planet indeed. We will have to wait for the future availability of new instruments to obtain an image of the planet.

The content in heavy chemical elements of 14 Her is rather large compared to that of the Sun. This discovery reinforces the suggestion that giant planets are more frequently observed around metal-rich stars. Heavy chemical elements are needed to form dust or ice particles, and then by agglomeration, planetesimals and the cores of giant planets. If the quantity of dust is large enough, this is certainly a factor in favor of the formation of giant planets.

Location Constellation: Hercules Right Ascension: 16 10 23.59 Declination: +43 49 18.2 Distance from Sol: 59.19 Light Years Basic Data Alternate Designations: HD 145675 HD 145675 Gl614 Spectral Type: K0 V Apparent Magnitude: 6.67 Mass: 1 Solar Masses Radius: 1.05 Solar Radii Effective Temperature: 5250 Kelvin Age: 3900 Million Years Habitability Inner Edge of Habitability Zone: 0.43 AU Outer Edge of Habitability Zone: 1.35 AU

14 Herculis b

14 Herculis b Statistics

Planetary Orbit Of HD 149026 b