Pi Mensae b

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Pi Mensae b
Exoplanet List of exoplanets
Parent star
Star Pi Mensae
Constellation Mensa
Right ascension (α) 05h 37m 09.89s
Declination (δ) –80° 28′ 08.84″
Apparent magnitude (mV) 5.67
Distance 59.39 ly
(18.21 pc)
Spectral type G1IV
Orbital elements
Semi-major axis (a) 3.38±0.22[1] AU
(506 Gm)
    186 mas
Periastron (q) 1.22 AU
(182 Gm)
Apastron (Q) 5.54 AU
(830 Gm)
Eccentricity (e) 0.6405±0.0072[1]
Orbital period (P) 2151 ± 85[1] d
(5.89 ± 0.23[1] y)
Argument of
(ω) 330.24 ± 0.67[1]°
Time of periastron (T0) 2,447,820 ± 170[1] JD
Semi-amplitude (K) 196.4 ± 1.3[1] m/s
Physical characteristics
Minimum mass (m sin i) 10.27 ± 0.84[1] MJ
(3265 M)
Discovery information
Discovery date 15 October 2001
Discoverer(s) Jones et al.[2]
Discovery method Doppler spectroscopy
Discovery site Australia Anglo-Australian
Discovery status Published
Other designations
HD 39091 b
Database references
Extrasolar Planets
Exoplanet Archive data
Open Exoplanet Catalogue data

Pi Mensae b (π Men b, π Mensae b), also known as HD 39091 b, is an extrasolar planet[1] approximately 59 light-years away in the constellation of Mensa. The planet was announced orbiting the yellow subgiant star Pi Mensae in October 2001.

Detection and discovery[edit]

On October 15, 2001, a team of astronomers including Jones, Butler, Tinney, Marcy, Penny, McCarthy, Carter, and Pourbaix announced the discovery of one of the most massive extrasolar planets that have yet been observed. It was discovered by the Anglo-Australian Planet Search team, using a Doppler spectrometer mounted on the Anglo-Australian Telescope.

Physical characteristics[edit]

Pi Mensae b has a very eccentric orbit and takes 5.89 years to revolve around the star. The semi-major axis of the planet to the star is 3.38 AU while the semi-minor axis is 2.59 AU. This planet passes through the star's habitable zone at periastron (1.21 AU)[citation needed] while at apastron, it passes to beyond Jupiter-Sun distance (5.54 AU). The gravitational influence of this planet would disrupt the orbit of any potentially Earth-like planet.[citation needed]

Pi Mensae b is over ten times more massive than Jupiter,[3] the most massive planet in our solar system. It will have 10 times the surface gravity of Jupiter alone and could be incandescent (glowing).[citation needed] The inclination of the orbit is not known, and it could be a brown dwarf instead.

See also[edit]


External links[edit]

  • "HD 39091". Exoplanets. Retrieved 2008-07-28. 
  • "Pi Mensae". SolStation. Retrieved 2008-07-28. 
  • "Pi Mensae". Планетные Системы (in Russian). Retrieved 2008-07-28. 

Coordinates: Sky map 05h 37m 09.89s, −80° 28′ 08.84″