Tau¹ Gruis

Tau¹ Gruis
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Grus
Right ascension 22h 53m 37.9315s
Declination –48° 35′ 53.828″
Apparent magnitude (V) +6.03
Characteristics
Spectral type G0V
U−B color index 0.19
B−V color index 0.62
Variable type None
Astrometry
Radial velocity (Rv) –1.1 km/s
Proper motion (μ) RA: +216.70 mas/yr
Dec.: –81.49 mas/yr
Parallax (π) 30.04 ± 0.73 mas
Distance 108.58 ly
(33.29 pc)
Absolute magnitude (MV) +3.42
Details
Mass 1.25 M☉
Radius 2 ± 0.7 R☉
Surface gravity (log g) 3.49
Luminosity 3.95 L☉
Temperature 5767 K
Metallicity 0.15 (141%)
Age 5.27 × 109 years
Other designations
CP(D) –49º 11672, CD –49° 13988, GC 31913, GSC 09340-01818, GJ 9802, HR 8700, HD 216435, HIP 113044, SAO 231343
Database references
SIMBAD data
ARICNS data

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. In 2002, one extrasolar planet was confirmed to orbit the star.

Contents

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 thought 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 it significantly older than previously predicted.

Planetary system

On September 17, 2002, a team of astronomers led by Geoffrey Marcy announced the discovery of a giant planet around Tau¹ Gruis.[1] 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.

The Tau1 Gruis system[2]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity
b >1.26 ± 0.13 MJ 2.56 ± 0.17 1311 ± 49 0.070 ± 0.078

See also

References

  1. ^ Jones et al.; Butler, R. Paul; Tinney, C. G.; Marcy, Geoffrey W.; Penny, Alan J.; McCarthy, Chris; Carter, Brad D. (2003). "An exoplanet in orbit around τ1 Gruis". Monthly Notices of the Royal Astronomical Society 341 (3): 948–952. arXiv:astro-ph/0209302. Bibcode 2003MNRAS.341..948J. doi:10.1046/j.1365-8711.2003.06481.x. http://www3.interscience.wiley.com/journal/118873416/abstract.  (web Preprint)
  2. ^ Butler et al.; Wright, J. T.; Marcy, G. W.; Fischer, D. A.; Vogt, S. S.; Tinney, C. G.; Jones, H. R. A.; Carter, B. D. et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal 646 (1): 505–522. arXiv:astro-ph/0607493. Bibcode 2006ApJ...646..505B. doi:10.1086/504701. http://www.iop.org/EJ/article/0004-637X/646/1/505/64046.html. 

External links

Coordinates: 22h 53m 37.9315s, −48° 35′ 53.828″

Stars of Grus
Bayer
Nearby