Mu Persei, Latinised from μ Persei, is a

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 ...

system in the northern constellation of

Perseus In Greek mythology, Perseus (Help:IPA/English, /ˈpɜːrsiəs, -sjuːs/; Greek language, Greek: Περσεύς, Romanization of Greek, translit. Perseús) is the legendary founder of Mycenae and of the Perseid dynasty. He was, alongside Cadmus ...

. It is visible to the naked eye as a point of light 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 +4.16. The distance to this system is approximately 900

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 101 ...

s 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 object ...

measurements. It is drifting further away 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 rate of change of the distance or range between the two points. It is equivalent to the vector projection ...

of +26 km/s. Mu Persei is a spectroscopic binary with an

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

of 284 days and an

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 ...

of about 0.06. The primary component is a yellow

G-type Gaea Gaea is one of the Elder Gods of Earth. Gaia Gaia, also known as the Guardian of the Universal Amalgamator, is a fictional superhero, depicted as possibly being a mutant or extraterrestrial. Created by Larry Hama, she first appeared in ...

supergiant Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram with absolute visual magnitudes between about −3 and −8. The temperature range of supergiant stars s ...

star. With 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 about and a radius of 53

solar radii Solar radius is a unit of distance used to express the size of stars in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: :1\,R_ = 6.957\t ...

, this star has the luminosity of about 2,030 times that of the Sun.MU PER (Mu Persei)
/ref> The companion is a

B-type star A B-type main-sequence star (B V) is a main-sequence (hydrogen-burning) star of spectral type B and luminosity class V. These stars have from 2 to 16 times the mass of the Sun and surface temperatures between 10,000 and 30,000 K. B-type stars ...

with a class of B9.5 Mu Persei is moving through the galaxy at a speed of 35.6 km/s relative to the Sun. Its projected galactic orbit carries it between 23,900 and 32,400 light-years from the center of the galaxy.Mu Persei (HIP 19812)
Mu Persei came closest to the Sun 5.6 million years ago when it had brightened to magnitude 3.25 from a distance of 600 light-years.

Naming

In Chinese, (), meaning '' Celestial Boat'', refers to an asterism consisting of μ Persei, η Persei, γ Persei, α Persei, ψ Persei, δ Persei, 48 Persei and HD 27084. Consequently, μ Persei itself is known as (, en, the Seventh Star of Celestial Boat).AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日
/ref>

References

{{DEFAULTSORT:Mu Persei G-type supergiants Spectroscopic binaries Perseus (constellation) Persei, Mu Durchmusterung objects Persei, 51 026630 019812 1303