XO-2 b
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| Extrasolar planet | List of extrasolar planets | |
|---|---|---|
| Parent star | ||
| Star | XO-2 | |
| Constellation | Lynx | |
| Right ascension | (α) | 07h 48m 07s |
| Declination | (δ) | +50° 13′ 33″ |
| Distance | 486 ± 13 ly (149 ± 4 pc) | |
| Spectral type | K0V | |
| Orbital elements | ||
| Semimajor axis | (a) | 0.0369±0.002 AU |
| Eccentricity | (e) | 0 |
| Orbital period | (P) | 2.615838±0.000006 d |
| Inclination | (i) | >88.58° |
| Angular distance | (θ) | 0.248 mas |
| Longitude of periastron |
(ω) | ?° |
| 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/m3 |
| Surface gravity | (g) | 1.42 m/s² |
| Temperature | (T) | 1208 K |
| Discovery information | ||
| Discovery date | 2007 | |
| Discoverer(s) | Burkes et al. | |
| Detection method | Transit | |
| Discovery status | Published | |
XO-2b is an extrasolar planet orbiting the star XO-2 in the constellation Lynx. This planet was found by transit method in 2007 by Burkes et al. This was the second such planet found by the XO telescope.
Like the types of planets found by transit method, it is a hot Jupiter – Jupiter-like planets that orbit very close to their stars; in this case, it suffers temperature of about 1200 K. 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.
[edit] References
- Christopher J. Burke, P. R. McCullough, J. A. Valenti, F. J. Summers, J. E. Stys, C. M. Johns-Krull, K. A. Janes, J. N. Heasley, R. Bissinger, M. Fleenor, C. N. Foote, E. Garcia-Melendo, B. L. Gary, P. J. Howell, F. Mallia, G. Masi, T. Vanmunster (2007). "XO-2b: A Transiting Hot Jupiter in a Metal-rich Common Proper Motion Binary". American Astronomical Society 39 (033.02).
- BURKE Ch., McCULLOUGH P., VALENTI J., JOHNS-KRULL Ch., JANES K., HEASLEY J., SUMMERS F., STYS J., BISSINGER R., FLEENOR M., FOOT C., GARCIA-MELENDO E., GARY B., HOWELL P., MALLIA F., MASI G., TAYLOR B. & VANMUSTER T. (2007). "XO-2b: Transiting Hot Jupiter in a Metal-rich Common Proper Motion Binary". Astronomy & Astrophysics.
