XO-4 is a

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

located approximately 863

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

s away from

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

in the

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 ...

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 ...

. It has a

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

of about 11 and cannot be seen with the naked eye but is visible through a small

telescope A telescope is a device used to observe distant objects by their emission, Absorption (electromagnetic radiation), absorption, or Reflection (physics), reflection of electromagnetic radiation. Originally, it was an optical instrument using len ...

. A search for a binary companion star using

adaptive optics Adaptive optics (AO) is a technique of precisely deforming a mirror in order to compensate for light distortion. It is used in Astronomy, astronomical telescopes and laser communication systems to remove the effects of Astronomical seeing, atmo ...

MMT Observatory The MMT Observatory (MMTO) is an astronomical observatory on the site of Fred Lawrence Whipple Observatory (IAU observatory code 696). The Whipple observatory complex is located on Mount Hopkins, Arizona, US (55 km south of Tucson) in the ...

was negative. The star XO-4 is named Koit. 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 ...

. Koit is Estonian for ''dawn'', 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 ...

Planetary system

One known

exoplanet 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 det ...

, XO-4b, which is classified as a

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 ...

, orbits XO-4. This exoplanet was discovered in 2008 by the

XO Project The XO Project is an international team of amateur and professional astronomers tasked with identifying extrasolar planets. They are led by Peter R. McCullough of the Space Telescope Science Institute. It is primarily funded by NASA's Origins Pro ...

using 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 ...

. It has been named Hämarik, meaning ''dusk'', and referring to a character from the same Faehlmann story featuring Koit. The planetary orbit is misaligned with the stellar rotation.

Notes

References

External links

* F-type main-sequence stars Lynx (constellation) Planetary transit variables Planetary systems with one confirmed planet

1721 Events January–March * January 6 – The Committee of Inquiry on the collapse of the South Sea Company in Great Britain publishes its findings. * February 5 – James Stanhope, chief minister of Great Britain, dies a day after ...

51234631

Koit KOIT (96.5 FM) is a commercial adult contemporary radio station licensed to San Francisco, California. The station has studios along Junipero Serra Boulevard in Daly City, and transmits from Sutro Tower in San Francisco, with a power outpu ...

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