Upsilon Piscium is a solitary, white-hued

star A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but their immense distances from Earth make ...

in the

zodiac The zodiac is a belt-shaped region of the sky that extends approximately 8° north or south (as measured in celestial latitude) of the ecliptic, the apparent path of the Sun across the celestial sphere over the course of the year. The p ...

constellation of

Pisces Pisces may refer to: * Pisces, an obsolete (because of land vertebrates) taxonomic superclass including all fish *Pisces (astrology), an astrological sign *Pisces (constellation), a constellation **Pisces Overdensity, an overdensity of stars in t ...

. It is faintly visible to the naked eye, having an

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 +4.75. Based upon an annual parallax shift of as seen from Earth, it is located about 308

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. The star is drifting further away with a heliocentric

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 +6 km/s. This is an ordinary

A-type main sequence star An A-type main-sequence star (A V) or A dwarf star is a main-sequence (hydrogen-burning) star of spectral type A and luminosity class V (five). These stars have spectra defined by strong hydrogen Balmer absorption lines. They measure between 1 ...

with a

stellar classification 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 t ...

of A3 V. It is 461 million years old – about 98% of the way through its

main sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...

lifetime – and is spinning 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 91 km/s. The star has 2.8 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 of ...

, about 2.2 times the Sun's radius, and is radiating 117 times the

Sun's luminosity The solar luminosity (), is a unit of radiant flux ( power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nomi ...

from its

photosphere The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it ...

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 9183 K.

Naming

υ Piscium is the

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. T ...

for this star, which is Latinized as Upsilon Piscium. It has the

Flamsteed designation A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the modern constellations visible from southern England. They are named for John Flamsteed who first used them while c ...

90 Piscium. In Chinese, (), meaning ''

Legs A leg is a weight-bearing and animal locomotion, locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single ...

(asterism)'', refers to an asterism composed of υ Piscium, η Andromedae, 65 Piscium,

ζ Andromedae Zeta Andromedae (Zeta And, ζ Andromedae, ζ And) is a star system in the constellation Andromeda. It is approximately 189 light-years from Earth. Zeta Andromedae is the star's Bayer designation. It also has the F ...

ε Andromedae Epsilon Andromedae, Latinized from ε Andromedae, is a star in the constellation of Andromeda. It can be seen with the naked eye, having an apparent visual magnitude of 4.4. Based upon an annual parallax shift of 21.04 ...

δ Andromedae Delta Andromedae, Latinized from δ Andromedae, is a triple star system in the northern constellation of Andromeda. The system is visible to the naked eye as a point of light with a combined apparent visual magnitude of 3.28. Based up ...

π Andromedae Pi Andromedae (Pi And, π Andromedae, π And) is the Bayer designation for a binary star system in the northern constellation of Andromeda. With an apparent visual magnitude of 4.4, it is visible to the naked eye. It i ...

, ν Andromedae,

μ Andromedae Mu Andromedae (Mu And, μ Andromedae, μ And) is the Bayer designation for a star in the northern constellation of Andromeda. It has an apparent visual magnitude of 3.87, making it readily visible to the naked eye. Based ...

β Andromedae Beta Andromedae, Latinized from β Andromedae, and officially named Mirach , is a prominent star in the northern constellation of Andromeda. It is northeast of the Great Square of Pegasus and is potentially visible to all observers ...

, σ Piscium,

τ Piscium Tau Piscium (τ Piscium) is an orange-hued star in the zodiac constellation of Pisces. With an apparent visual magnitude of +4.52, it is a dim star but visible to the naked eye. Based upon an annual parallax shift of 19.32 ...

, 91 Piscium, φ Piscium,

χ Piscium Chi Piscium (χ Piscium) is a solitary, orange-hued star in the zodiac constellation of Pisces. It can be seen with the naked eye, having an apparent visual magnitude of +4.64. Based upon an annual parallax shift of 8.50 mas as ...

and ψ¹ Piscium. 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 oft ...

for υ Piscium itself is (, en, the Thirteenth Star of Legs.)AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日
/ref>

References

{{DEFAULTSORT:Upsilon Piscium A-type main-sequence stars Pisces (constellation) Piscium, Upsilon Durchmusterung objects Piscium, 090 007964 006193 0383