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

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

in the

zodiac The zodiac is a belt-shaped region of the sky that extends approximately 8° north and south celestial latitude of the ecliptic – the apparent path of the Sun across the celestial sphere over the course of the year. Within this zodiac ...

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 ...

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 whose recognition pred ...

. It has an

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 +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 centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

is about 474

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, as determined by

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 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) ...

. A

super-Jupiter A super-Jupiter is a gas giant exoplanet that is more massive than the planet Jupiter. For example, substellar companion, companions at the planet–brown dwarf borderline have been called super-Jupiters, such as around the star Kappa Andromedae. ...

brown dwarf Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main sequence, main-sequence stars. Their mass is approximately 13 to 80 Jupiter mass, times that of Jupiter ()not big en ...

is known to orbit it, and another is suspected.

Properties

Mu² Scorpii 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 ...

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 gratin ...

of B2 IV. It has an estimated diameter of 5.6

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 ...

and a mass of 9.1 times the

Sun's mass The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies a ...

, 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 s ...

. The large mass of this star make it a

supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...

progenitor. 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 . It is some 20 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 bu ...

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 alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...

. 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 Lam ...

and Lesath in the tip of the tail of Scorpio, and in another they become Mu² and Mu¹ Scorpii. (In a similar version of the story told in the

Cook Islands The Cook Islands is an island country in Polynesia, part of Oceania in the South Pacific Ocean. It consists of 15 islands whose total land area is approximately . The Cook Islands' Exclusive Economic Zone (EEZ) covers of ocean. Avarua is its ...

, 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 China, ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categori ...

, 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

Planetary system

Two sub-stellar objects slightly above deuterium burning limit (

s) were found in 2022 by direct imaging near Mu² Scorpii. The outer one, designated μ² 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 151985 082545 6252 Upper Centaurus Lupus Durchmusterung objects Pipirima Planetary systems with one confirmed planet