XO-2Nb (XO-2Bb)
Extrasolar planet List of extrasolar planets
Size comparison of XO-2 b (gray) with Jupiter.
Parent star

<tr> <td colspan="2">Star</td> <td>XO-2N (XO-2B)</td></tr><tr> <td colspan="2">Constellation</td> <td>Lynx[1]</td></tr><tr> <td>Right ascension</td> <td style="text-align: center">(α)</td> <td>07h 48m 06.468s [2]</td></tr><tr> <td>Declination</td> <td style="text-align: center">(δ)</td> <td>+50° 13′ 32.96″ [2]</td></tr><tr><td colspan="2">Distance</td><td>483 ± 33 [3] ly
(148 ± 10 [3] pc)</td></tr><tr><td colspan="2">Spectral type</td> <td>K0V [4]</td></tr>

Orbital elements

<tr><td>Semimajor axis</td><td style="text-align: center">(a)</td> <td>0.0369 ± 0.002 AU</td></tr><tr> <td>Eccentricity</td> <td style="text-align: center">(e)</td> <td>0</td></tr><tr><td>Orbital period</td><td style="text-align: center">(P)</td> <td>2.61586178 ± 0.00000075[5] d</td></tr><tr> <td>Inclination</td> <td style="text-align: center">(i)</td> <td>87.62 ± 0.51[5]°</td></tr><tr> <td>Argument of
</td> <td style="text-align: center">(ω)</td> <td>?°</td></tr><tr> <td>Time of periastron</td> <td style="text-align: center">(T0)</td> <td>2454147.74902 ± 0.00002 JD</td></tr><tr> <td>Semi-amplitude</td> <td style="text-align: center">(K)</td> <td>80.2 m/s</td></tr>

Physical characteristics

<tr><td>Mass</td><td style="text-align: center">(m)</td><td>0.57 ± 0.06 MJ</td></tr><tr><td>Radius</td><td style="text-align: center">(r)</td><td>0.973 ± 0.03 Template:Jupiter radius</td></tr><tr><td>Density</td><td style="text-align: center">(ρ)</td><td>820 kg m-3</td></tr><tr><td>Surface gravity</td><td style="text-align: center">(g)</td><td>1.42 m/s²</td></tr><tr> <td>Temperature</td> <td style="text-align: center">(T)</td> <td>1208 K</td></tr>

Discovery information

<tr> <td colspan="2">Discovery date</td> <td>2007</td></tr><tr> <td colspan="2">Discoverer(s)</td> <td>Burke et al.</td></tr><tr> <td colspan="2">Discovery method</td> <td>Transit (including secondary eclipse)</td></tr><tr> <td colspan="2">Other detection methods</td> <td>Radial velocity</td></tr><tr> <td colspan="2">Discovery status</td> <td>Published</td></tr> <tr style="background-color: #A0B0FF;"><td align=center colspan=3>Database references</td></tr><tr valign=baseline><td colspan=2>Extrasolar Planets
</td><td>data</td></tr><tr><td colspan=2>SIMBAD</td><td>data</td></tr>

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.

File:XO-2 b rv.pdf

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 alsoEdit


  1. (1987). Identification of a Constellation From a Position. Publications of the Astronomical Society of the Pacific 99 (617): 695–699. Vizier query form
  2. 2.0 2.1 Hog et al. (2000). Tyc 3413-5-1. The Tycho-2 Catalogue. Retrieved 2012-01-07.
  3. 3.0 3.1 (2008). Improved Parameters for Extrasolar Transiting Planets. The Astrophysical Journal 677 (2): 1324–1342.
  4. 4.0 4.1 (2007). XO-2b: Transiting Hot Jupiter in a Metal-rich Common Proper Motion Binary. The Astrophysical Journal 671 (2): 2115–2128.
  5. 5.0 5.1 (2011). Gran Telescopio Canarias OSIRIS transiting exoplanet atmospheric survey: detection of potassium in XO-2b from narrowband spectrophotometry. Astronomy and Astrophysics 527.
  6. XO-2 b SIMBAD query result:XO-2b -- Extra-solar Planet Candidate. Centre de Données astronomiques de Strasbourg. Retrieved 2009-04-26.

External linksEdit


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

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