Phi Ursae Majoris, Latinized from φ Ursae Majoris, is

binary star A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in wh ...

system in the

northern Northern may refer to the following: Geography * North, a point in direction * Northern Europe, the northern part or region of Europe * Northern Highland, a region of Wisconsin, United States * Northern Province, Sri Lanka * Northern Range, a ra ...

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 ...

Ursa Major Ursa Major (; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear," referring to and contrasting it with nearby Ursa ...

. It is white-hued and is visible to the naked eye with a combined

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...

of +4.60; the primary is magnitude 5.28 while the secondary is magnitude 5.39. The system is located at a distance of approximately from the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

based on

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 ...

, but is drifting closer with a

radial velocity The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...

of −14.7 km/s. It should make its closest approach at a distance of around in about 4.7 million years. As of 2017, the components had an

angular separation Angular distance \theta (also known as angular separation, apparent distance, or apparent separation) is the angle between the two sightlines, or between two point objects as viewed from an observer. Angular distance appears in mathematics (in pa ...

of along a

position angle In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the north celestial pole (NCP), turning positive into the d ...

of 304°. They are orbiting each other with a

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

of 105.4 years and

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-center, in geometry * Eccentricity (graph theory) of a v ...

of 0.44. Both of components are A-type

subgiant A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution of ...

stars 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 A3 IV. Phi Ursae Majoris is moving through the galaxy at a speed of 21.6 km/s relative to the Sun. Its projected galactic orbit carries it between 24,000 and 46,000 light-years from the center of the galaxy.

Naming

With τ, h, υ, θ, e, and f, it composed the Arabic asterism ''Sarīr Banāt al-Na'sh'', the Throne of the daughters of ''Na'sh'', and ''Al-Haud'', the Pond. According to the catalogue of stars in the ''Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars'', ''Al-Haud'' were the title for seven stars: f as ''Alhaud I'', τ as ''Alhaud II'', e as ''Alhaud III'', h as ''Alhaud IV'', θ as ''Alhaud V'', υ as ''Alhaud VI'' and this star (φ) as ''Alhaud VII''. 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 ''

Administrative Center An administrative center is a seat of regional administration or local government, or a county town, or the place where the central administration of a commune A commune is an alternative term for an intentional community. Commune or comună or ...

'', refers to an asterism consisting of φ Ursae Majoris, υ Ursae Majoris,

θ Ursae Majoris Theta Ursae Majoris (Theta UMa, θ Ursae Majoris, θ UMa) is a suspected spectroscopic binary star system in the northern circumpolar constellation of Ursa Major. It has an apparent visual magnitude of 3.17, placing it amon ...

, 15 Ursae Majoris and 18 Ursae Majoris. Consequently, the

Chinese name Chinese names or Chinese personal names are names used by individuals from Greater China and other parts of the Chinese-speaking world throughout East and Southeast Asia (ESEA). In addition, many names used in Japan, Korea and Vietnam are often a ...

for φ Ursae Majoris itself is known as (, en, the Third Star of Administrative Center).

References

{{Stars of Ursa Major A-type subgiants Binary stars Ursa Major Ursae Majoris, Phi Ursae Majoris, 30 Durchmusterung objects 085235 048402 3894 Alhaud VII