Rho Persei, Latinized from ρ Persei, is a

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

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 origins of the e ...

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 has the traditional name Gorgonea Tertia , being the third member of the quartet called the Gorgonea in reference to the Gorgons from the legend of

. An apparent visual magnitude of +3.39 makes it visible to the naked eye, but a challenge to view from a well-lit urban environment. 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 is located at a distance of roughly from

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

Rho Persei is a

semiregular variable star In astronomy, a semiregular variable star, a type of variable star, is a giant or supergiant of intermediate and late (cooler) spectral type showing considerable periodicity in its light changes, accompanied or sometimes interrupted by various irre ...

, whose

apparent 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 li ...

varies between 3.3 and 4.0 with periods of 50, 120 and 250 days. The star has reached the

asymptotic giant branch The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars. This is a period of stellar evolution undertaken by all low- to intermediate-mass stars (about 0.5 to 8 solar masses) lat ...

of its

evolution 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 ...

. It is a

bright giant A giant star is a star with substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Press ...

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 M4 II. The outer envelope has 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 3,479 K, giving it the red-orange hue of an M-type star. This star has a mass 1.9 times 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 ...

, while its radius has expanded to 143 times solar. It is radiating some 2,700 times the Sun's luminosity. Rho Persei is losing mass at the rate of

solar mass 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 ...

es per year, or the equivalent of the Sun's mass every 83 million years. It is about 440 million years in age.

Naming

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 ''

Mausoleum A mausoleum is an external free-standing building constructed as a monument enclosing the interment space or burial chamber of a deceased person or people. A mausoleum without the person's remains is called a cenotaph. A mausoleum may be consid ...

'', refers to an asterism consisting of ρ Persei,

9 Persei 9 Persei is a single variable star in the northern constellation Perseus, located around 4,300 light years away from the Sun. It has the Bayer designation i Persei; ''9 Persei'' is the Flamsteed designation. This body is visible t ...

, τ Persei, ι Persei, κ Persei, β Persei,

16 Persei 16 Persei is a single, suspected variable star in the northern constellation of Perseus (constellation), Perseus, located approximately 121 light years away based on parallax. It is visible to the naked eye as a yellow-white hued star wit ...

and

12 Persei 12 Persei (12 Per) is a double-lined spectroscopic binary star system in the northern constellation Perseus. Its combined apparent magnitude is 4.94, which means it can be viewed with the naked eye. Based upon parallax measurements, this ...

. Consequently, the Chinese name for ρ Persei itself is (, en, the Sixth Star of Mausoleum.).AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日
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References

External links

{{DEFAULTSORT:Rho Persei M-type giants Asymptotic-giant-branch stars Semiregular variable stars Zeta Herculis Moving Group Perseus (constellation) Persei, Rho BD+38 0630 Persei, 25 019058 014354 0921 Gorgonea Tertia