GQ Lupi b

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**GQ Lupi b**
Parent star
Extrasolar planet		List of extrasolar planets
Star		GQ Lupi
Constellation		Lupus
Right ascension	(α)	15^h 49^m 12.14^s
Declination	(δ)	-35° 39′ 03.9″
Distance		400 ly (123 pc)
Spectral type		K7V
Orbital elements
Observed separation	(d)	103 ± 37 AU
Physical characteristics
Mass	(m)	1 – 42 M_J
Radius	(r)	1.2 ± 0.6 R_J
Temperature	(T)	1600 – 2520 K
Discovery information
Discovery date		4 April 2005
Discoverer(s)		Neuhäuser et al.
Detection method		Imaged
Discovery site		Chile
Discovery status		Published

GQ Lupi b is a possible extrasolar planet orbiting the star GQ Lupi. At its discovery in 2005, it was believed to be the first extrasolar planet to be directly imaged, although 2M1207b may also claim that distinction (and neither may be planets). The image was made with the VLT telescope at Paranal Observatory, Chile in April 2005.

Located at a distance of about 100 AU from its companion star, giving it an orbital period of about 1200 years, GQ Lupi b is believed to be several times more massive than Jupiter. Because the theoretical models which are used to predict planetary masses for objects in young star systems like GQ Lupi b are still tentative, the mass cannot be precisely specified -- although most estimates give a mass of about 2 to 3 times that of Jupiter, other models place GQ Lupi b's mass anywhere between 1 and 42 Jupiter masses. At the highest end of this range, GQ Lupi b would be classified as a small brown dwarf in a binary star system rather than as an exoplanet. The object has a spectral type between M9 and L4, corrseponding to a temperature between 1600 and 2500 kelvin.

As of May 2005, the International Astronomical Union describes GQ Lupi b as a "possible planetary-mass companion to a young star."