Mu Arae b

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Mu Arae b
Exoplanet List of exoplanets
Parent star
Star Mu Arae
Constellation Ara
Right ascension (α) 17h 44m 08.7s
Declination (δ) −51° 50′ 03″
Apparent magnitude (mV) 5.15
Distance 50.6 ± 0.2 ly
(15.51 ± 0.07 pc)
Spectral type G3IV–V
Mass (m) 1.10 ± 0.01 M
Radius (r) 1.36 ± 0.01 R
Temperature (T) 5820 ± 40 K
Metallicity [Fe/H] 0.30 ± 0.01
Age 6.34 ± 0.40 Gyr
Orbital elements
Semimajor axis (a) 1.497[1] AU
(223.9 Gm)
Periastron (q) 1.304 AU
(195.1 Gm)
Apastron (Q) 1.689 AU
(252.6 Gm)
Eccentricity (e) 0.128[1]
Orbital period (P) 643.25 ± 0.90[1] d
(1.7611 y)
Argument of
(ω) 22.0 ± 7.0[1]°
Time of periastron (T0) 2452365.6 ± 12.6[1] JD
Semi-amplitude (K) 37.78 ± 0.40 m/s
Physical characteristics
Minimum mass (m sin i) 1.676[1] MJ
(533 M)
Discovery information
Discovery date December 12, 2000
Discoverer(s) Butler, Marcy
Discovery method Doppler Spectroscopy
Discovery site California,  USA
Discovery status Published
Other designations
HD 160691 b
Database references
Extrasolar Planets
Exoplanet Archive data
Open Exoplanet Catalogue data

Mu Arae b (also referred to as HD 160691 b) is an exoplanet orbiting the star Mu Arae of the constellation Ara. It is at least one and a half times the mass of Jupiter, and its orbital period is 643.25 days. The discovery of this planet was announced on December 12, 2002, and was originally thought to be on a highly eccentric orbit.[2] The latest models of the its planetary system, which has four known planets, give a lower eccentricity orbit.[1] Although the planet itself is likely to be a gas giant with no solid surface, the orbital distance of 1.497 astronomical units from its star puts it within the habitable zone of its planetary system. As a result, large satellites, if they exist, of the planet, could potentially support life. However, it may not receive enough ultraviolet light for abiogenesis to proceed.[3] Furthermore, it is not clear that Earth-size moons can actually be formed in the environment around a gas giant planet.[4]

The planet and its host star is one of the planetary systems selected by the International Astronomical Union as part of their public process for giving proper names to exoplanets and their host star (where no proper name already exists).[5][6] The process involves public nomination and voting for the new names, and the IAU plans to announce the new names in mid-November 2015.[7]


  1. ^ a b c d e f g Pepe, F.; Correia, A. C. M.; Mayor, M.; Tamuz, O.; et al. (2007). "The HARPS search for southern extra-solar planets. VIII. μ Arae, a system with four planets". Astronomy and Astrophysics 462 (2): 769–776. arXiv:astro-ph/0608396. Bibcode:2007A&A...462..769P. doi:10.1051/0004-6361:20066194. 
  2. ^ Butler, R. Paul; Tinney, C. G.; Marcy, Geoffrey W.; Jones, Hugh R. A.; et al. (2001). "Two New Planets from the Anglo-Australian Planet Search". The Astrophysical Journal 555 (1): 410–417. Bibcode:2001ApJ...555..410B. doi:10.1086/321467. 
  3. ^ Buccino, Andrea P.; Lemarchand, Guillermo A.; Mauas, Pablo J. D. (2006). "Ultraviolet Radiation Constraints around the Circumstellar Habitable Zones". Icarus 183 (2): 491–503. arXiv:astro-ph/0512291. doi:10.1016/j.icarus.2006.03.007. 
  4. ^ Canup, R.; Ward, W. (2006). "A common mass scaling for satellite systems of gaseous planets". Nature 441 (7095): 834–839. Bibcode:2006Natur.441..834C. doi:10.1038/nature04860. PMID 16778883. 
  5. ^ NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars. 9 July 2014
  6. ^ NameExoWorlds.
  7. ^ NameExoWorlds.

Coordinates: Sky map 17h 44m 08.7s, −51° 50′ 03″