Gamma Cephei Ab

Planetbox begin
name = Gamma Cephei Ab Planetbox star
star = Gamma Cephei A
constell = Cepheus
RA = RA|23|39|20.8
DEC = DEC|+77|37|56
dist_ly = 44.9 ± 0.3cite journal|url=http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?2007A%26A...462..777N&db_key=AST&nosetcookie=1|title=Direct detection of exoplanet host star companion γ Cep B and revised masses for both stars and the sub-stellar object|author=Neuhäuser, R.; Mugrauer, M.; Fukagawa, M.; Torres, G.; Schmidt, T.|year=2007|journal=Astronomy and Astrophysics|volume=462|issue=2|pages=777–780|doi=10.1051/0004-6361:20066581]
dist_pc = 13.76 ± 0.08
class = K1IVe Planetbox orbit
semimajor = 2.044 ± 0.057
eccentricity = 0.115 ± 0.058
period = 902.9 ± 3.5
period_year = 2.472 ± 0.010
ang_dist = 173.22
long_peri = 63 ± 27
t_peri = 2,453,156.8 ± 52.4
semi-amp = 27.5 ± 1.5 Planetbox character
mass = >1.60 ± 0.13Planetbox discovery
discovery_date = 13 July 1988 (suspected)
24 September 2002
discoverers = Hatzes "et al."
discovery_method = Doppler spectroscopy
discovery_site = flag|United States
discovery_status = Confirmed

Gamma Cephei Ab is an extrasolar planet approximately 45 light-year away in the constellation of Cepheus (the King). The planet was confirmed to orbit Gamma Cephei in 2002, but was suspected to be a planet around 1988 (making this planet the first "true" extrasolar planet discovered).

Detection and discovery

1988 claims

The first indications of Gamma Cephei Ab were reported in July of 1988. The planet was tentatively identified by a Canadian team of astronomers (lead by Bruce Campbell, Gordon Walker, and Stephenson Yang, while its existence was also announced by Anthony Lawton and P. Wright in 1989. Though not confirmed, this world would have been the first "true" extrasolar planet, and it was hypothesized based on the same radial velocity technique later used successfully by others. However, the claim was retracted in 1992 due to the quality of the data not being good enough to make a solid discovery.

2002 confirmation

On September 24 2002, Gamma Cephei Ab was finally confirmed. The team of astronomers (including William D. Cochran, Artie P. Hatzes... etc.) at the Planetary Systems and their Formation Workshop announced the preliminary confirmation of a long-suspected planet Gamma Cephei Ab with a minimum mass of 1.59 times that of Jupiter. [cite journal | author=Hatzes "et al."| title =A Planetary Companion to Gamma Cephei A | journal=The Astrophysical Journal | year=2003 | volume=599 | issue=2 | pages=1383 – 1394 | url=http://www.journals.uchicago.edu/doi/full/10.1086/379281| doi =10.1086/379281] The parameters were later recalculated when direct detection of the secondary star Gamma Cephei B allowed astronomers to better constrain the properties of the system. Gamma Cephei Ab moves in an elliptical orbit with a semimajor axis of 2.044 AU which takes almost two and a half years to complete. The eccentricity is 0.115, which means it moves between 1.81 and 2.28 AUs in orbital distance around Gamma Cephei A, which would place it beyond the orbit of Mars in the solar system.

Hipparcos data taken in 2006 constrains its mass below "13.3MJup at the 95% confidence level, and 16.9MJup at the 99.73% (3 σ) confidence level". This is not much to go on, but it is enough to verify that it is not another unseen red or brown dwarf.cite journal | journal=The Astrophysical Journal | volume=654 | issue=2 | page=1095–1109 | url=http://www.journals.uchicago.edu/doi/abs/10.1086/509715 | format=abstract | title=The Planet Host Star γ Cephei: Physical Properties, the Binary Orbit, and the Mass of the Substellar Companion | author=Guillermo Torres | year=2007 | doi=10.1086/509715]

See also

* 51 Pegasi b
* Iota Horologii b
* PSR B1257+12 B
* PSR B1257+12 C

References

External links

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