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
Semi-major 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
Quijote, HD 160691 b
Database references
Extrasolar Planets
Exoplanet Archive data
Open Exoplanet Catalogue data

Mu Arae b, often designated HD 160691 b, later named Quijote, is an extrasolar planet orbiting the star Mu Arae of the constellation Ara.

The planet 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.[improper synthesis?] 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]

In July 2014 the International Astronomical Union launched a process for giving proper names to certain exoplanets and their host stars.[5] The process involved public nomination and voting for the new names.[6] In December 2015, the IAU announced the winning name was Quijote for this planet.[7] The winning name was submitted by the Planetario de Pamplona, Spain. Quijote was the lead character of the novel El Ingenioso Hidalgo Don Quixote de la Mancha.[8]


  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/0608396Freely accessible. 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/0512291Freely accessible. 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 The Process
  7. ^ Final Results of NameExoWorlds Public Vote Released, International Astronomical Union, 15 December 2015.
  8. ^ NameExoWorlds The Approved Names

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