Mu Persei, Latinised from μ Persei, is a

binary star A binary star or binary star system 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 as separate stars us ...

system in the northern

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 ...

Perseus In Greek mythology, Perseus (, ; Greek language, Greek: Περσεύς, Romanization of Greek, translit. Perseús) is the legendary founder of the Perseid dynasty. He was, alongside Cadmus and Bellerophon, the greatest Greek hero and slayer of ...

. 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, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light ca ...

of +4.16. The distance to this system is approximately 900

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 based on

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

measurements. It is drifting further away with a

radial velocity The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity ...

of +26 km/s. Mu Persei is a

spectroscopic binary A binary star or binary star system 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 as separate stars us ...

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-Centre (geometry), center, in geometry * Eccentricity (g ...

of about 0.06. The primary component is a yellow G-type

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 temperatures of supergiant stars range ...

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 may refer to: Astronomy * Of or relating to the Sun ** Solar telescope, a special purpose telescope used to observe the Sun ** A device that utilizes solar energy (e.g. "solar panels") ** Solar calendar, a calendar whose dates indicat ...

, 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 In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...

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 Eta Persei (η Persei, abbreviated Eta Per, η Per), is a red supergiant in the constellation of Perseus. Parallax measurements by the Gaia spacecraft imply that it is 1,000 is light-years away from Earth. At such distance, interstellar ...

γ Persei Gamma Persei (Gamma Per, γ Persei, γ Per) is a binary star system in the constellation Perseus (constellation), Perseus. The combined apparent visual magnitude of the pair is +2.9, making it the fourth-brightest member of ...

α Persei Alpha Persei ( Latinized from α Persei, abbreviated Alpha Per, α Per), formally named Mirfak (pronounced or ), is the brightest star in the northern constellation of Perseus, outshining the constellation's best-known st ...

ψ Persei Psi Persei (Psi Per, ψ Persei, ψ Per) is a single Be star in the northern constellation of Perseus. It has an apparent visual magnitude of about 4.2, so it is visible to the naked eye at night under suitably dark skies ...

δ Persei Delta Persei (Delta Per, δ Persei, δ Per) is a double star in the northern constellation of Perseus. It has an apparent visual magnitude of 3.01, making it readily visible with the naked eye. Parallax measurements give i ...

48 Persei 48 Persei (also known as c Persei, 48 Per, HR 1273, HIP 19343, or ) is a Be star in the constellation Perseus, approximately the 500th brightest of the visible stars in apparent magnitude. It is "well known for its complex spectrum and ...

and

HD 27084 HD may refer to: Business * H-D or Harley-Davidson, a motorcycle manufacturer * The Home Depot, NYSE stock symbol: HD Chemistry * Hydrogen deuteride, a diatomic compound of hydrogen and deuterium * Mustard gas Codes * Air Do, formerly H ...

. Consequently, μ Persei itself is known as (, ).AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日

References

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

1303 Year 1303 ( MCCCIII) was a common year starting on Tuesday of the Julian calendar. Events January–March * January 17 – A major earthquake strikes Byzantium and Constantinople (now Istanbul in Turkey). Byzantine Emperor Michael IX ...