HD 217107 b

Planetbox begin
name = HD 217107 bPlanetbox star
star = HD 217107
constell = Pisces
ra = RA|22|58|15.54
dec = DEC|−2|23|43.39
dist_ly = 64.3 ± 1
dist_pc = 19.7 ± 0.3
class = G8IVPlanetbox orbit
separation =
position_angle =
semimajor = 0.074 ± 0.002
eccentricity = 0.13 ± 0.02
period = 7.1269 ± 0.00022
inclination =
ang_dist = 1.973
long_peri = 21.1
arg_peri =
t_peri = 2,449,998.4241 ± 0.17
t_transit =
t_approach =
semi-amp = 140.7 ± 2.6Planetbox character
mass = >1.37 ± 0.14
radius =
density =
gravity =
temperature = ~1013Planetbox discovery
discovery_date = 24 November 1998
discoverers = Marcy "et al."
discovery_method = Doppler spectroscopy
discovery_site = flag|United States
discovery_status = Confirmed

HD 217107 b is an extrasolar planetcite journal | url=http://www.journals.uchicago.edu/doi/full/10.1086/432901 | author=Vogt "et al." | title=Five New Multicomponent Planetary Systems| journal=The Astrophysical Journal| year=2005 | volume=632 | issue=1 | pages=638 – 658 | doi=10.1086/432901] approximately 46 light-years away in the constellation of Pisces (the Fish). The planet was discovered orbiting the star HD 217107 approximately every seven days, classifying the planet as a hot Jupiter. Because of the planet's somewhat eccentric orbit, scientists were able to confirm another planet within the system (HD 217107 c).

Discovery

As with the majority of extrasolar planet discoveries so far, it was found by detecting small variations in the radial velocity of the star it orbits, caused by the tug of its gravity.A study of the radial velocity of HD 217107 carried out in 1998 revealed that its motion along the line of sight varied over a 7.1 day cycle. The period and amplitude of this variation indicated that it was caused by a planetary companion in orbit around the star, with a minimum mass slightly greater than that of Jupiter. [cite journal | url=http://www.journals.uchicago.edu/doi/full/10.1086/316304 | author=Fischer "et al." | title=Planetary Companions around Two Solar-Type Stars: HD 195019 and HD 217107 | journal=Publications of the Astronomical Society of the Pacific | year=1999 | volume=111 | issue=755 | pages=50 – 56 | doi=10.1086/316304] The planet's mean distance from the star is less than one fifth of Mercury's distance from the Sun.

Indication of second planet

While most planets with orbital periods of less than 10 days have almost circular orbits, HD 217107 b has a somewhat eccentric orbit, and its discoverers hypothesised that this could be due to the gravitational influence of a second planet in the system at a distance of several astronomical units (AU). [cite journal | url=http://www.journals.uchicago.edu/doi/full/10.1086/320224 | author=Fischer "et al." | title=Planetary Companions to HD 12661, HD 92788, and HD 38529 and Variations in Keplerian Residuals of Extrasolar Planets | journal=The Astrophysical Journal | year=2002 | volume=551 | issue=2 | pages=1107 – 1118 | doi=10.1086/320224] Confirmation of the existence of a second planet, HD 217107 c, followed in 2005.

See also

* HD 217107 c

References

External links

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