14 Herculis b

14 Herculis b

Extrasolar planet		List of extrasolar planets
14 Herculis b in Celestia as a ammonia cloud gas giant
Parent star
Star		14 Herculis
Constellation		Hercules
Right ascension	(α)	16h 10m 23.59s
Declination	(δ)	+43° 49′ 18.2″
Apparent magnitude	(mV)	6.67
Distance		59.0 ly (18.1 pc)
Spectral type		K0V
Mass	(m)	0.79 M☉
Radius	(r)	0.88 R☉
Temperature	(T)	5250 K
Metallicity	[Fe/H]	0.35
Age		3.9 Gyr
Orbital elements
Semimajor axis	(a)	2.77 ± 0.05[1] AU
Eccentricity	(e)	0.369 ± 0.005[1]
Orbital period	(P)	1773.4 ± 2.5[1] d
Argument of periastron	(ω)	22.6 ± 0.9[1]°
Time of periastron	(T0)	2,451,372.7 ± 3.6[1] JD
Semi-amplitude	(K)	90.0 ± 0.5[1] m/s
Physical characteristics
Minimum mass	(m sin i)	4.64 ± 0.19[1] MJ
Discovery information
Discovery date		6 July 1998
Discoverer(s)		Naef et al.
Discovery method		Doppler spectroscopy
Discovery site		Switzerland
Discovery status		Published
Database references
Extrasolar Planets Encyclopaedia		data
SIMBAD		data
Exoplanet Archive		data
Open Exoplanet Catalogue		data

14 Herculis b or 14 Her b is an extrasolar planet approximately 59 light-years away in the constellation of Hercules. The planet was found orbiting the star 14 Herculis, with a mass that would likely make the planet a Jovian planet roughly the same size as Jupiter but much more massive. It was discovered in July 1998 by the Geneva Extrasolar Planet Search team.^[2][3] At the time of discovery it was the extrasolar planet with the longest orbital period, though longer-period planets have subsequently been discovered.

Discovery

Radial velocity changes over time of 14 Herculis caused by the orbit of 14 Herculis b.

Like the majority of known extrasolar planets, 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.^[3]

Orbit and mass

Preliminary astrometric measurements made by the Hipparcos satellite suggest 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, so the actual inclination and true mass of the planet remains unknown.^[4] Its inclination is being calculated via astrometry with Hubble. The astrometricians expect publication by mid-2009.^[5] It may also be targeted by future astrometric missions such as Gaia and the Space Interferometry Mission.

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.^[6]

References

External links

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

Coordinates: 16^h 10^m 23.59^s, +43° 49′ 18.2″