Omicron¹ Eridani (ο¹ Eridani, abbreviated Omicron¹ Eri, ο¹ Eri), also named Beid , is a

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as ...

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 origins of the e ...

of Eridanus. With an average apparent visual magnitude of 4.04, it is visible to the naked eye on a clear, dark night. Based upon

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

measurements, it lies approximately 122

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s from the Sun.

Nomenclature

''ο¹ Eridani'' ( Latinised to ''Omicron¹ Eridani'') is the star's

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. ...

. The system bears the traditional name ''Beid'' derived from the

Arabic Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...

word بيض meaning "eggs" (cf. neighboring

Keid 40 Eridani is a triple star system in the constellation of Eridanus, abbreviated 40 Eri. It has the Bayer designation Omicron2 Eridani, which is Latinized from ο2 Eridani and abbreviated Omicron2 Eri or ο2 Eri. Based on parallax ...

"(egg)shells"). In 2016, the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

organized a

Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...

(WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name ''Beid'' for this star on 12 September 2016 and it is now so included in the List of IAU-approved Star Names. In

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of va ...

, (), meaning '' Interpreters of Nine Dialects'', refers to an asterism consisting of Omicron¹ Eridani,

39 Eridani 39 Eridani is a wide binary star system in the equatorial constellation of Eridanus. It is visible to the naked eye as a faint, orange-hued star with a combined apparent visual magnitude of 4.87. As of 2015, the components had an angular ...

Xi Eridani ξ Eridani (Latinised as Xi Eridani) is a solitary star in the constellation Eridanus. With an apparent visual magnitude of 5.17, it is faintly visible to the naked eye on a clear, dark night. Based upon an annual parallax shift of 0.0015 ...

Nu Eridani Nu Eridani (ν Eri) is a star in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.93. The distance to this star is roughly 520 light years, based upon an annual parallax shift of 0.00 ...

56 Eridani This is the list of notable stars in the constellation Eridanus, sorted by decreasing brightness. See also *List of stars by constellation All stars but one can be associated with an IAU constellation. IAU constellations are areas of the sky. ...

and

55 Eridani This is the list of notable stars in the constellation Eridanus, sorted by decreasing brightness. See also *List of stars by constellation All stars but one can be associated with an IAU constellation. IAU constellations are areas of the sky. ...

. Consequently, the Chinese name for Omicron¹ Eridani itself is (, en, the Second Star of Interpreters of Nine Dialects).

Properties

Omicron¹ Eridani is an

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation t ...

F-type giant star with a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

of F0 III. It is a Delta Scuti variable star that undergoes non-radial pulsations, with a variation of just 0.03 magnitude over a period of 0.0747 days. The star is spinning rapidly with a

projected rotational velocity Stellar rotation is the angular motion of a star about its axis. The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface. The rotation of a star produces an equatorial bulge ...

of 108.1 km/s and a rotation period of less than around 1.9 days. This is creating an equatorial bulge that is 11% wider than the polar radius. Omicron¹ Eridani has nearly double the

mass of the Sun The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...

, 3.7 times the Sun's radius, and shines with 27 times the solar luminosity from an outer atmosphere at an

effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...

of 6,963 K.

References

External links

* {{DEFAULTSORT:Omicron1 Eridani F-type giants Delta Scuti variables Eridanus (constellation)

Beid Omicron1 Eridani (ο1 Eridani, abbreviated Omicron1 Eri, ο1 Eri), also named Beid , is a variable star in the constellation of Eridanus. With an average apparent visual magnitude of 4.04, it is visible to the naked eye on a clear, dar ...

Eridani, Omicron1 Eridani, 38 026574 019587

1298 Year 1298 ( MCCXCVIII) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. Events By place Europe * April 20 – Rindfleisch massacres: The Jews of Röttingen are burned en mass ...

Durchmusterung objects