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Exoplanet List of exoplanets
Exoplanet Comparison HAT-P-9 b.png
Size comparison of HAT-P-9b with Jupiter.
Parent star
Star HAT-P-9
Constellation Auriga
Right ascension (α) 07h 20m 40.479s
Declination (δ) +37° 08′ 26.17″
Distance1560 ± 190 ly
(480 ± 60 pc)
Spectral type F
Orbital elements
Semi-major axis(a) 0.0528 ± 0.002 AU
Periastron (q) 0.0527 AU
Apastron (Q) 0.0529 AU
Eccentricity (e) ~0.0012
Orbital period(P) 3.92289 ± 0.00004 d
(0.0107401 y)
Time of transit (Tt) 2454417.9077 ± 0.0003 JD
Physical characteristics
Mass(m)0.78 ± 0.09 MJ
(250 M)
Radius(r)1.4 ± 0.06 RJ
(15 R)
(96 Mm)
Density(ρ)380 kg m−3
Surface gravity(g)10.3 m/s² (1.05 g)
Discovery information
Discovery date June 26, 2008
Discoverer(s) Shporer et al.
Discovery method Transit (SuperWASP)
Discovery site Cambridge, Massachusetts
Discovery status Published
Database references
Extrasolar Planets
Exoplanet Archivedata
Open Exoplanet Cataloguedata

HAT-P-9b is an exoplanet approximately 1560 light years away in the constellation Auriga. This planet was found by the transit method on June 26, 2008. It has a mass 78% that of Jupiter and a radius 140% that of Jupiter. As with most transiting planets, this planet is a hot Jupiter, meaning this Jupiter-like planet orbits extremely close to its parent star, taking only 3.92 days to orbit.[1]


  1. ^ Shporer, Avi; et al. (2009). "HAT-P-9b: A Low-Density Planet Transiting a Moderately Faint F Star". The Astrophysical Journal. 690 (2): 1393–1400. arXiv:0806.4008Freely accessible. Bibcode:2009ApJ...690.1393S. doi:10.1088/0004-637X/690/2/1393. 

External links[edit]

Media related to HAT-P-9b at Wikimedia Commons

Coordinates: Sky map 07h 20m 40.479s, +37° 08′ 26.17″