XO-4b is an

extrasolar planet An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first detect ...

approximately 956

light year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by t ...

s away in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Lynx A lynx ( ; : lynx or lynxes) is any of the four wikt:extant, extant species (the Canada lynx, Iberian lynx, Eurasian lynx and the bobcat) within the medium-sized wild Felidae, cat genus ''Lynx''. The name originated in Middle Engl ...

. This planet was found by the

transit method Methods of detecting exoplanets usually rely on indirect strategies – that is, they do not directly image the planet but deduce its existence from another signal. Any planet is an extremely faint light source compared to its parent star. For e ...

by McCullough in May 2008. The planet has mass and radius . This planet orbits very close to the

F-type F-type may refer to: *F-type asteroid, a type of carbonaceous asteroid *F-ATPase, a membrane protein *F-type main-sequence star, a hydrogen-fusing star * F-type Prisons, high-security prisons in Turkey *MG F-type Magna, six-cylinder-engined car pr ...

parent star, as it is typical for transiting planets, classing this planet as

Hot Jupiter Hot Jupiters (sometimes called hot Saturns) are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter (i.e. Jupiter analogue, Jupiter analogues) but that have very short orbital periods (). The close proximity to t ...

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. The study in 2012, utilizing a

Rossiter–McLaughlin effect The Rossiter–McLaughlin effect is a spectroscopic phenomenon observed when an object moves across the face of a rotating star. The star is seen to undergo a redshift anomaly caused by the obscuration of different parts of its disk. Descriptio ...

, have determined the planetary orbit is strongly misaligned with the equatorial plane of the star, misalignment equal to -46.7°.

Naming

The planet XO-4b is named Hämarik. The name was selected in the

NameExoWorlds NameExoWorlds (also known as IAU NameExoWorlds) were various projects managed by the International Astronomical Union (I.A.U.) to encourage names to be submitted for astronomical objects, notably exoplanets. The accepted names would later be cons ...

campaign by

Estonia Estonia, officially the Republic of Estonia, is a country in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the Baltic Sea across from Sweden, to the south by Latvia, and to the east by Ru ...

, during the 100th anniversary of the

IAU The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

. Hämarik is Estonian for dusk, and was named for a character in a folk tale written by

Friedrich Robert Faehlmann Friedrich Robert Faehlmann (Fählmann) (31 December 1798 in Ao Manor, Kreis Jerwen – 22 April 1850 in Tartu) was an Estonian writer, medical doctor and philologist active in Livonia, Russian Empire. He was a co-founder of the Learned Estonia ...

References

External links

* Hot Jupiters Lynx (constellation) Transiting exoplanets Giant planets Exoplanets discovered in 2008 Exoplanets with proper names {{extrasolar-planet-stub

Orbit

Naming

See also

References

External links