HD 154345 b

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HD 154345 b
Exoplanet List of exoplanets
Parent star
Star HD 154345
Constellation Hercules
Right ascension (α) 17h 02m 36.40s
Declination (δ) +47° 04′ 54.77″
Apparent magnitude (mV) 6.74
Distance 58.91 ± 0.59 ly
(18.06 ± 0.18 pc)
Spectral type G8V
Mass (m) 0.88 M
Orbital elements
Semi-major axis (a) 4.18 AU
(625 Gm)
    89.9 mas
Periastron (q) 4.03 AU
(603 Gm)
Apastron (Q) 4.33 AU
(647 Gm)
Eccentricity (e) 0.036 ± 0.046
Orbital period (P) 3322 ± 93 d
(9.095 y)
Orbital speed (υ) 13.7 km/s
Inclination (i) 50+40
Argument of
(ω) 113°
Time of periastron (T0) 2,453,230 ± 330 JD
Semi-amplitude (K) 14.28 ± 0.75 m/s
Physical characteristics
Mass (m) 1.2+1.3
[1] MJ
Discovery information
Discovery date March 12, 2006
(confirmed: May 27, 2007)
Discoverer(s) Wright et al.
Discovery method radial velocity
Discovery site United States
Discovery status published
Database references
Extrasolar Planets
Exoplanet Archive data
Open Exoplanet Catalogue data

HD 154345 b, is a Jupiter-sized extrasolar planet orbiting the star HD 154345.


Wright et al. discovered the planet in March 2006 using the radial velocity method to detect the small wobbling movement of the star caused by the gravity of the planet. The discovery was confirmed in May 2007.[2]


The planet has a mass at least slightly less than that of Jupiter. It orbits its parent star at the distance of 4.18 AU. Its orbital period is about 9.095 Earth years and its orbit is circular. There are no interior planets of minimum mass (m sini) greater than 0.3 Jupiter.[3] Jupiter-like planets with these orbital and system characteristics are unlikely to be perturbed from the star's inclination.[4] Since the star's inclination is known as around 50°, this would make the planet's most likely mass greater than Jupiter's mass but less than twice that mass.[5]

As such HD 154345 b is presumed to be a gas giant "Jupiter twin".[3] Depending on composition the two planets may be around the same size, or HD 154345 b may be larger. This planet may also harbor a system of moons and rings.[citation needed]

See also[edit]


  1. ^ a b Simpson, E. K.; et al. (November 2010), "Rotation periods of exoplanet host stars", Monthly Notices of the Royal Astronomical Society, 408 (3): 1666–1679, arXiv:1006.4121Freely accessible, Bibcode:2010MNRAS.408.1666S, doi:10.1111/j.1365-2966.2010.17230.x 
  2. ^ Wright, J. T.; et al. (2007). "Four New Exoplanets and Hints of Additional Substellar Companions to Exoplanet Host Stars". The Astrophysical Journal. 657 (1): 533–545. arXiv:astro-ph/0611658Freely accessible. Bibcode:2007ApJ...657..533W. doi:10.1086/510553. 
  3. ^ a b Wright, J. T.; et al. (2008). "The Jupiter Twin HD 154345b". The Astrophysical Journal Letters. 683 (1): L63–L66. arXiv:0802.1731Freely accessible. Bibcode:2008ApJ...683L..63W. doi:10.1086/587461. 
  4. ^ Roberto Sanchis-Ojeda; Josh N. Winn; Daniel C. Fabrycky (2012). "Starspots and spin-orbit alignment for Kepler cool host stars". arXiv:1211.2002Freely accessible. Bibcode:2013AN....334..180S. doi:10.1002/asna.201211765. 
  5. ^ "hd_154345_b". Extrasolar Planet Encyclopaedia. Retrieved November 12, 2012. 

Coordinates: Sky map 17h 02m 36.40s, +47° 04′ 54.77″