XO-2 (star)

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Observation data
Epoch 2000      Equinox 2000
Constellation Lynx[1]
Right ascension 07h 48m 06.468s[2]
Declination +50° 13′ 32.96″[2]
Apparent magnitude (V) 11.18 ± 0.03[3]
Spectral type  ? + K0V
Proper motion (μ) RA: -34.7 ± 2.6[2] mas/yr
Dec.: -153.6 ± 2.4[2] mas/yr
Distance 483 ± 33[4] ly
(148 ± 10[4] pc)
XO-2 S
Mass 0.982 ± 0.034[5] M
Radius 1.02[5] R
Temperature 5399 ± 55 [5] K
Metallicity [Fe/H] 0.39 ± 0.05[5] dex
Age 7.1 ± +2.5
[5] Gyr
XO-2 N
Mass 0.971 ± 0.034[6] M
Radius 0.976+0.024
[6] R
Temperature 5340 ± 32[3] K
Age 6.3 ± 2.4[6] Gyr
Other designations
TYC 3413-5-1, GSC 03413-00005, 2MASS J07480647+5013328[7]
Database references

XO-2 Is a binary star. It consists of two components: XO-2S (Also known as XO-2A) and XO-2N (Also known as XO-2B).[5]

This system is located approximately 480 light-years away[4] from Earth in the Lynx constellation. Both of these stars are slightly cooler than the Sun and are nearly identical to each other. The system has a magnitude of 11 and cannot be seen with the naked eye but is visible through a small telescope. These stars are also notable for their large proper motions.[7]

XO-2N and XO-2S have a separation of approximately 4,600 AU.[3]

Planetary systems[edit]

One known exoplanet, XO-2Nb (or rarely XO-2Bb), which is classified as a hot Jupiter, was discovered by the XO Telescope using the transit method orbiting XO-2N (XO-2B) in 2007.[3]

Two planets were reported to orbit around XO-2S in 2014 using radial velocity method. One of them is Jupiter-mass and another has a mass comparable to Saturn.[5]

Both stars also show RV-trends, which may indicate the presence of additional long-periodic jovians or brown dwarfs around each of them.

The XO-2S planetary system[5]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b ≥ 0.259 ± 0.014 MJ 0.1344 ±0.0025 18.157 ± 0.034 0.18 ± 0.035
c ≥ 1.37 ± 0.053 MJ 0.4756 ±0.0087 120.8 ± 0.034 0.1528 ± 0.01
The XO-2N planetary system[8][9]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b 0.62 ± 0.02 MJ 0.0369 ±0.002 2.61586178 ± 0.00000075 0.045 ± 0.024 88.7 ± 1.3° 0.973 ± 0.03 RJ

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 c d Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISBN 0-333-75088-8. doi:10.1888/0333750888/2862.  Vizier catalog entry
  3. ^ a b c d Burke, Christopher J.; McCullough, P. R.; Valenti, Jeff A.; Johns‐krull, Christopher M.; Janes, Kenneth A.; Heasley, J. N.; Summers, F. J.; Stys, J. E.; Bissinger, R.; Fleenor, Michael L.; Foote, Cindy N.; Garcia‐Melendo, Enrique; Gary, Bruce L.; Howell, P. J.; Mallia, F.; Masi, G.; Taylor, B.; Vanmunster, T. (2007). "XO-2b: Transiting Hot Jupiter in a Metal-rich Common Proper Motion Binary". The Astrophysical Journal. 671 (2): 2115–2128. Bibcode:2007ApJ...671.2115B. arXiv:0705.0003Freely accessible. doi:10.1086/523087. 
  4. ^ a b c Torres, Guillermo; Winn, Joshua N.; Holman, Matthew J. (2008). "Improved Parameters for Extrasolar Transiting Planets". The Astrophysical Journal. 677 (2): 1324–1342. Bibcode:2008ApJ...677.1324T. arXiv:0801.1841Freely accessible. doi:10.1086/529429. 
  5. ^ a b c d e f g h Desidera, S.; Bonomo, A. S.; Claudi, R. U.; Damasso, M.; Biazzo, K.; Sozzetti, A.; Marzari, F.; Benatti, S.; Gandolfi, D.; Gratton, R.; Lanza, A. F.; Nascimbeni, V.; Andreuzzi, G.; Affer, L.; Barbieri, M.; Bedin, L. R.; Bignamini, A.; Bonavita, M.; Borsa, F.; Calcidese, P.; Christille, J. M.; Cosentino, R.; Covino, E.; Esposito, M.; Giacobbe, P.; Harutyunyan, A.; Latham, D.; Lattanzi, M.; Leto, G.; et al. (2014). "The GAPS programme with HARPS-N@TNG IV: A planetary system around XO-2S". Astronomy & Astrophysics. 567 (6): L6. Bibcode:2014A&A...567L...6D. arXiv:1407.0251Freely accessible. doi:10.1051/0004-6361/201424339. 
  6. ^ a b c Fernandez, Jose M.; Holman, Matthew J.; Winn, Joshua N.; Torres, Guillermo; Shporer, Avi; Mazeh, Tsevi; Esquerdo, Gilbert A.; Everett, Mark E. (2009). "The Transit Light Curve Project. XII. Six Transits of the Exoplanet XO-2b". The Astronomical Journal. 137 (6): 4911–4916. Bibcode:2009AJ....137.4911F. arXiv:0903.2687Freely accessible. doi:10.1088/0004-6256/137/6/4911. 
  7. ^ a b "TYC 3413-5-1 -- High proper-motion Star". Centre de Données astronomiques de Strasbourg. Retrieved 2012-01-15. 
  8. ^ Narita, Norio; Hirano, Teruyuki; Sato, Bun’ei; Harakawa, Hiroki; Fukui, Akihiko; Aoki, Wako; Tamura, Motohide (2011). "XO-2b: a Prograde Planet with a Negligible Eccentricity and an Additional Radial Velocity Variation". Publications of the Astronomical Society of Japan. 63 (6): L67–L71. Bibcode:2011PASJ...63L..67N. arXiv:1110.6136Freely accessible. doi:10.1093/pasj/63.6.l67. 
  9. ^ Sing, D. K.; Désert, J.-M.; Fortney, J. J.; Lecavelier Des Etangs, A.; Ballester, G. E.; Cepa, J.; Ehrenreich, D.; López-Morales, M.; Pont, F.; Shabram, M.; Vidal-Madjar, A. (2011). "Gran Telescopio Canarias OSIRIS transiting exoplanet atmospheric survey: detection of potassium in XO-2b from narrowband spectrophotometry". Astronomy and Astrophysics. 527: A73. Bibcode:2011A&A...527A..73S. arXiv:1008.4795Freely accessible. doi:10.1051/0004-6361/201015579. 

External links[edit]

Coordinates: Sky map 07h 48m 06.468s, +50° 13′ 32.96″