GJ 3021

Starbox begin
name = GJ 3021Starbox observe
epoch = J2000.0
constell = Hydrus
ra = RA|00|16|12.6775
dec = DEC|-79|51|04.254
appmag_v = 6.59Starbox character
class = G6V
r-i =
v-r =
b-v = 0.749
u-b =
variable = Starbox astrometry
radial_v =
prop_mo_ra =
prop_mo_dec =
parallax =
p_error =
parallax_footnote =
dist_ly = 57.47
dist_pc = 17.62
space_v_u =
space_v_v =
space_v_w =
absmag_v = Starbox detail
source =
mass = 0.9
radius = 0.86
gravity =
luminosity =
temperature = 5417
metal = 0.2 [Fe/H]
rotation = 5.5 km/s
age = 800 millionStarbox catalog
names = HD 1237, HIP 1292Starbox reference
Simbad = HD+1237
ARICNS =

GJ 3021, formally cataloged as Gliese 3021, is a binary star system approximately 57 light-years away in the constellation of Hydrus (the Water Snake).

The visible star in the system, A, is considered to be a Solar twin. As of 2000, it has been confirmed that an extrasolar planet orbits the star. It is of note for being a relatively sun-like star not very far from the Sun that is home to an extrasolar planet. [cite journal | url= http://www.aanda.org/articles/aa/full/2001/31/aa10239/aa10239.html | author=Naef "et al." | title=The CORALIE survey for southern extrasolar planets V. 3 new extrasolar planets | journal = Astronomy and Astrophysics | year=2001 | volume=375 | issue=1 | pages=205–218 ] .

Stellar components

As a nearby sun-like star, the last decade has seen GJ 3021A being studied carefully for the first time, especially after its substellar companion was discovered. It is currently believed that it is 800 million years old, though age estimates range from 150 million to 8.8 billion years old depending on the method used for the determination [cite journal | url=http://www.aanda.org/articles/aa/full/2005/44/aa3452-05/aa3452-05.html | author=Saffe, C. "et al." | title=On the Ages of Exoplanet Host Stars | journal=Astronomy and Astrophysics | volume=443 | issue=2 | pages=609–626 | year=2005 | doi=10.1051/0004-6361:20053452] . The star is more enriched with iron than the Sun, is chromospherically active, and rotates around its axis more quickly than the Sun.The secondary star GJ 3021B is a M4 red dwarf star at a projected physical separation of 68 AU. [ Cite journal | url=http://www.aanda.org/articles/aa/abs/2007/44/aa7046-06/aa7046-06.html | title=Characterization of the long-period companions of the exoplanet host stars: HD 196885, HD 1237 and HD 27442 | author=Chauvin "et al." | journal=Astronomy and Astrophysics | year=2007 | volume=475 | issue=2 | pages=723–727 | doi=10.1051/0004-6361:20067046 | format=abstract ( [http://arxiv.org/abs/0710.5918 web preprint] ) ]

Planetary system

Announced in 2000, the Jovial planet GJ 3021 b orbits about 0.5 astronomical units from GJ 3021 A with a minimum mass 3.37 times that of Jupiter, as determined by measuring variations in the radial velocity of the star. A study published in 2001 suggested that the usual inability to determine the orbital inclination of an extrasolar planet through radial velocity measurement had caused this mass to be severely underestimated. [ cite journal | url=http://www.journals.uchicago.edu/doi/full/10.1086/318927 | author=Han "et al." | title=Preliminary astrometric masses for proposed extrasolar planetary companions | journal=The Astrophysical Journal | volume=548| issue=1 | pages=L57 – L60 | year=2001 | doi=10.1086/318927 ] The astrometric orbit gives an orbital inclination of 11.8° and a mass of 16 Jupiter masses, which would make the object a brown dwarf. However later analysis showed that Hipparcos was not sensitive enough to accurately determine astrometric orbits for substellar companions, which means the inclination (and hence the true mass) of the planet are still unknown. [cite journal | url=http://www.aanda.org/articles/aa/full/2001/24/aa1274/aa1274.html | title=Screening the Hipparcos-based astrometric orbits of sub-stellar objects | author=Pourbaix, D. and Arenou, F. | journal=Astronomy and Astrophysics |volume=372 | pages=935–944 | year=2001 | doi=10.1051/0004-6361:20010597]

PlanetboxOrbit
exoplanet = b
mass = >3.37
semimajor = 0.495
period = 133.71 ± 0.20
eccentricity = 0.511 ± 0.017

See also

*Epsilon Reticuli
*HD 196885
*List of stars with confirmed extrasolar planets

References

External links

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