Astronomy:XO-4b
 Size comparison of XO-4b with Jupiter. | |
| Discovery | |
|---|---|
| Discovered by | McCullough et al. |
| Discovery site | Maui, Hawaii |
| Discovery date | May 19, 2008 |
| Transit | |
| Orbital characteristics | |
| 0.0555 ± 0.00011 AU (8,303,000 ± 16,000 km) | |
| Eccentricity | 0.0024 |
| Orbital period | 4.12502 ± 2e-5 d 0.011293 y |
| Inclination | 88.7 ± 1.1 |
| Star | XO-4 |
| Physical characteristics | |
| Mean radius | 1.34 ± 0.048 |♃|J}}}}}} |
| Mass | 1.72 ± 0.2 |♃|J}}}}}} |
| Mean density | 948 kg/m3 (1,598 lb/cu yd) |
| 24.8 m/s2 (81 ft/s2) | |
| Physics | ~1333[clarification needed] |
XO-4b is an extrasolar planet approximately 956 light years away in the constellation of Lynx. This planet was found by the transit method by McCullough in May 2008. The planet has mass 1.72 |♃|J}}}}}} and radius 1.34 |♃|J}}}}}}. This planet orbits very close to the F-type parent star, as it is typical for transiting planets, classing this planet as Hot Jupiter.
Orbit
It takes only 4.125 days (or 99 hours) to orbit at a distance of 8.3 gigameters (0.0555 AU) away from the star.[1]
The study in 2012, utilizing a Rossiter–McLaughlin effect, have determined the planetary orbit is strongly misaligned with the equatorial plane of the star, misalignment equal to -46.7±8.1°.[2]
Naming
The planet XO-4b is named Hämarik. The name was selected in the NameExoWorlds campaign by Estonia, during the 100th anniversary of the IAU. Hämarik is Estonian for dusk, and was named for a character in a folk tale written by Friedrich Robert Faehlmann.[3][4][5]
See also
References
- ↑ McCullough, P. R.; et al. (2008). "XO-4b: An Extrasolar Planet Transiting an F5V Star". arXiv:0805.2921 [astro-ph].
- ↑ Albrecht, Simon; Winn, Joshua N.; Johnson, John A.; Howard, Andrew W.; Marcy, Geoffrey W.; Butler, R. Paul; Arriagada, Pamela; Crane, Jeffrey D. et al. (2012), "Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments", The Astrophysical Journal 757 (1): 18, doi:10.1088/0004-637X/757/1/18, Bibcode: 2012ApJ...757...18A
- ↑ "Approved names" (in en). http://www.nameexoworlds.iau.org/final-results.
- ↑ "International Astronomical Union | IAU". https://www.iau.org/news/pressreleases/detail/iau1912/.
- ↑ "Estonia has been assigned its own star and planet" (in en). 20 January 2020. https://estonianworld.com/knowledge/estonia-has-been-assigned-its-own-star-and-planet.
External links
Coordinates: 
07h 21m 33.1657s, +58° 16′ 05.005″
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