Tau1 Gruis

Starbox begin
name = Tau¹ GruisStarbox observe
epoch = J2000.0
constell = Grus
ra = RA|22|53|37.9315
dec = DEC|–48|35|53.828
appmag_v = +6.03Starbox character
class = G0V
b-v = 0.62
u-b = 0.19
variable = "None"Starbox astrometry
radial_v = –1.1
space_v_u = -39
space_v_v = -27
space_v_w = -16
prop_mo_ra = +216.70
prop_mo_dec = –81.49
gal_lat = −58.7099
gal_lon = +341.6935
parallax = 30.04
p_error = 0.73
dist_ly = 108.58
dist_pc = 33.29
absmag_v = +3.42Starbox detail
age = 5.27 × 10⁹
metal = 0.15 (141%)
mass = 1.25
radius = 2 ± 0.7
density = 220
gravity = 3.49
luminosity = 3.95
temperature = 5767Starbox catalog
names = CP(D) –49º 11672,
CD –49° 13988, GC 31913, GSC 09340-01818, GJ 9802, HR 8700, HD 216435, HIP 113044, SAO 231343Starbox reference
Simbad = HD+216435
ARICNS = 4c02857

Tau¹ Gruis (τ¹ Gru / τ¹ Gruis), also cataloged as HD 216435 and HR 8700, is a yellow dwarf star approximately 109 light-years away in the constellation of Grus (the Crane). The star is visible to the naked eye for some people, placing it in the Bright Star Catalogue. As of 2002, one extrasolar planet has been confirmed to orbit the star.

Characteristics

Tau¹ Gruis is a yellow dwarf star of the possible spectral type of G0-3 V-IV. It is thought that the star has about 1.25 times more mass than the Sun, a probable large radius, and about 3.6 times more luminosity. Due to its unusually brightness, at least one source suspects that the star may be a highly evolved subgiant star. It is though that Tau¹ Gruis is about 1.4 times more enriched with elements heavier than hydrogen, making a high abundance of iron likely. The Ca-II H line of the star suggests that it is chromospherically inactive, making its age significant older than previously predicted.

Planetary system

On September 17, 2002, a team of astronomers lead by Geoffrey Marcy announced the discovery of a giant planet around Tau¹ Gruis. The radial velocity measurements suggest that the star has a companion with at least 1.23 times the mass of Jupiter. The planet's orbit stays inside the system's habitable zone for most of its revolution around the star, though at apoapsis, the planet falls outside of this zone.

PlanetboxOrbit begin
name = Tau¹ GruisPlanetboxOrbit
exoplanet = b
mass = >1.26
semimajor = 2.561
period = 1311 ± 49
eccentricity = 0.0703 ± 0.0781

See also

* 55 Cancri
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References

* ( [http://arxiv.org/abs/astro-ph/0209302 web Preprint] )
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