XO-4b

XO-4b
Hämarik
Size comparison of XO-4b with Jupiter.
Discovery
Discovered byMcCullough et al.
Discovery siteMaui, Hawaii
Discovery dateMay 19, 2008
Transit
Orbital characteristics
0.0555 ± 0.00011 AU (8,303,000 ± 16,000 km)
Eccentricity0.0024
4.12502 ± 2e-5 d
0.011293 y
Inclination88.7 ± 1.1
StarXO-4
Physical characteristics
1.34 ± 0.048 RJ
Mass1.72 ± 0.2 MJ
Mean density
0.948 g/cm3[citation needed]
24.8 m/s2 (2.53 g0)
Temperature~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 MJ and radius 1.34 RJ. 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

  1. ^ McCullough, P. R.; et al. (2008). "XO-4b: An Extrasolar Planet Transiting an F5V Star". arXiv:0805.2921 [astro-ph].
  2. ^ Albrecht, Simon; Winn, Joshua N.; Johnson, John A.; Howard, Andrew W.; Marcy, Geoffrey W.; Butler, R. Paul; Arriagada, Pamela; Crane, Jeffrey D.; Shectman, Stephen A.; Thompson, Ian B.; Hirano, Teruyuki; Bakos, Gaspar; Hartman, Joel D. (2012), "Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments", The Astrophysical Journal, 757 (1): 18, arXiv:1206.6105, Bibcode:2012ApJ...757...18A, doi:10.1088/0004-637X/757/1/18, S2CID 17174530
  3. ^ "Approved names". NameExoworlds. Retrieved 2020-01-02.
  4. ^ "International Astronomical Union | IAU". www.iau.org. Retrieved 2020-01-02.
  5. ^ "Estonia has been assigned its own star and planet". Estonian World. 20 January 2020. Retrieved 2020-01-20.

Media related to XO-4b at Wikimedia Commons



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