Mu² Scorpii (μ² Scorpii, abbreviated Mu² Sco, μ² Sco), also named Pipirima , 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

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 Sun path, apparent path of the Sun across the celestial sphere over the course of the year. ...

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 ...

Scorpius Scorpius is a zodiac constellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation that pre-dates the Gre ...

. It has 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 +3.56, which is bright enough to be seen with the naked eye. Its distance 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 ...

is about 474

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, as determined by

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 a member of the Upper Centaurus–Lupus subgroup of the

Scorpius–Centaurus association The Scorpius–Centaurus association (sometimes called Sco–Cen or Sco OB2) is the nearest OB association to the Sun. This stellar association is composed of three subgroups (Upper Scorpius, Upper Centaurus–Lupus, and Lower Centaurus–Crux) ...

Properties

This is a blue-white, B-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 ...

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 B2 IV. It has an estimated 7 times the

radius of the Sun 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 ...

, almost 9 times the

Sun's 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 of ...

, and shines with 2,385 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 nominal ...

. The outer atmosphere 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 23,113 K. It is some 18.5 million years old 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 58 km/s.

Nomenclature

''μ² Scorpii'' ( Latinised to ''Mu² Scorpii'') is the star's

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. ...

. In Tahiti, a

traditional story Traditional stories, or stories about traditions, differ from both fiction and nonfiction in that the importance of transmitting the story's worldview is generally understood to transcend an immediate need to establish its categorization as imagi ...

is told of a brother and sister, named ''Pipiri'' and ''Rehua'', who flee their parents into the sky and become stars. Their parents call them ''Pipiri ma'' while chasing them into the sky: ''ma'' "with, and" is used after names to mean "et al." In one account, the children become

Shaula Lambda Scorpii is a triple star system and the second-brightest object in the constellation of Scorpius. It is formally named Shaula; ''Lambda Scorpii'' is its Bayer designation, which is Latinised from λ Scorpii and abbreviated Lamb ...

and

Lesath Upsilon Scorpii (υ Scorpii, abbreviated Upsilon Sco, υ Sco), formally named Lesath , is a star located in the "stinger" of the southern zodiac constellation of Scorpius, the scorpion. Based on parallax measurements obtained during the H ...

in the tip of the tail of Scorpio, and in another they become Mu² and

Mu¹ Scorpii Mu1 Scorpii (μ1 Scorpii, abbreviated Mu1 Sco, μ1 Sco) is a binary star system in the southern zodiac constellation of Scorpius. The combined apparent visual magnitude of the pair is about magnitude 3, making it one of the brighter m ...

. (In a similar version of the story told in the

Cook Islands ) , image_map = Cook Islands on the globe (small islands magnified) (Polynesia centered).svg , capital = Avarua , coordinates = , largest_city = Avarua , official_languages = , lan ...

, they become Omega¹ and Omega² Scorpii).Johannes Carl Andersen (1931) ''Myths and Legends of the Polynesians''. 1995 Dover reprint, p.400''ff''. In 2016, the IAU organized a

Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...

(WGSN) to catalog and standardize proper names for stars. The WGSN approved the name ''Pipirima'' for this star on 5 September 2017 (along with Xamidimura for its partner) and it is now so included in the List of IAU-approved Star Names. In

Chinese astronomy Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twe ...

, Mu² Scorpii is called 尾宿增二.AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 10 日
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Planetary system

Two sub-stellar objects slightly above deuterium burning limit (

brown dwarf Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most ...

s) were found in 2022 by direct imaging near Mu2 Scorpii. The outer one, designated Mu2 Scorpii b, is definitely an orbiting planet or brown dwarf, and the inner one is a planetary candidate.

References

External links

The beautiful maidens from the Once, Upon a Reef
on: Facebook, Cook Islands Dance Video's {{DEFAULTSORT:Mu2 Scorpii Scorpii, Mu2 B-type subgiants Scorpius (constellation) 151985 082545 6252 Upper Centaurus Lupus Durchmusterung objects

Pipirima Mu² Scorpii (μ² Scorpii, abbreviated Mu² Sco, μ² Sco), also named Pipirima , is a star in the zodiac constellation of Scorpius. It has an apparent visual magnitude of +3.56, which is bright enough to be seen with the naked eye. It ...

Planetary systems with one confirmed planet