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XO-2Nb (XO-2Bb)
Exoplanet List of exoplanets
Exoplanet Comparison XO-2 b.png
Size comparison of XO-2 b (gray) with Jupiter.
Parent star
Star XO-2N (XO-2B)
Constellation Lynx[1]
Right ascension (α) 07h 48m 06.468s [2]
Declination (δ) +50° 13′ 32.96″ [2]
Distance 483 ± 33 [3] ly
(148 ± 10 [3] pc)
Spectral type K0V [4]
Orbital elements
Semi-major axis (a) 0.0369 ± 0.002 AU
Eccentricity (e) 0
Orbital period (P) 2.61586178 ± 0.00000075[5] d
Inclination (i) 87.62 ± 0.51[5]°
Argument of
Time of periastron (T0) 2454147.74902 ± 0.00002 JD
Semi-amplitude (K) 80.2 m/s
Physical characteristics
Mass (m) 0.57 ± 0.06 MJ
Radius (r) 0.973 ± 0.03 RJ
Density (ρ) 820 kg m−3
Surface gravity (g) 1.42 m/s²
Temperature (T) 1208
Discovery information
Discovery date 2007
Discoverer(s) Burke et al.
Discovery method Transit (including secondary eclipse)
Other detection methods Radial velocity
Discovery status Published
Database references
Extrasolar Planets
Exoplanet Archive data
Open Exoplanet Catalogue data

XO-2Nb (or rarely XO-2Bb) is an extrasolar planet orbiting the star XO-2N, the fainter component of XO-2 wide binary star in the constellation Lynx.[6] This planet was found by transit method in 2007 by Burke et al. This was the second such planet found by the XO telescope.

The radial velocity of XO-2 over time, caused by the presence of XO-2 b.

Like most planets found by the transit method, it is a roughly Jupiter sized planet that orbits very close to its host star; in this case, it has a surface temperature of about 1200 K, so it belongs to a group of exoplanets known as hot Jupiters. The planet takes 2.6 days to orbit the star at the average distance of 0.0369 AU. The planet has mass of 57% of Jupiter and radius of 97% of Jupiter. The radius is relatively large for its mass, probably due to its intense heating from its nearby star that bloats the planet’s atmosphere. The large radius for its mass gives a low density of 820 kg/m3.[4]

See also[edit]


  1. ^ Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific. 99 (617): 695–699. Bibcode:1987PASP...99..695R. doi:10.1086/132034.  Vizier query form
  2. ^ a b Hog; et al. (2000). "Tyc 3413-5-1". The Tycho-2 Catalogue. Retrieved 2012-01-07. 
  3. ^ a b Torres, Guillermo; et al. (2008). "Improved Parameters for Extrasolar Transiting Planets". The Astrophysical Journal. 677 (2): 1324–1342. arXiv:0801.1841Freely accessible. Bibcode:2008ApJ...677.1324T. doi:10.1086/529429. 
  4. ^ a b Burke, Christopher J.; et al. (2007). "XO-2b: Transiting Hot Jupiter in a Metal-rich Common Proper Motion Binary". The Astrophysical Journal. 671 (2): 2115–2128. arXiv:0705.0003Freely accessible. Bibcode:2007ApJ...671.2115B. doi:10.1086/523087. 
  5. ^ a b Sing, D. K.; et al. (2011). "Gran Telescopio Canarias OSIRIS transiting exoplanet atmospheric survey: detection of potassium in XO-2b from narrowband spectrophotometry". Astronomy and Astrophysics. 527. article number A73. arXiv:1008.4795Freely accessible. Bibcode:2011A&A...527A..73S. doi:10.1051/0004-6361/201015579. 
  6. ^ "SIMBAD query result:XO-2b -- Extra-solar Planet Candidate". Centre de Données astronomiques de Strasbourg. Retrieved 2009-04-26. 

External links[edit]

Media related to XO-2b at Wikimedia Commons

Coordinates: Sky map 07h 48m 07s, +50° 13′ 33″