ω¹ Scorpii, Latinised as Omega¹ Scorpii, 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 ...

. With 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 3.95 it can be seen with the naked eye, 0.22 degree north of the ecliptic.

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 of this star give an estimated distance of around 470

light years 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 ...

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 ...

. It is a member 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) ...

. This is a

B-type main sequence star A B-type main-sequence star (B V) is a main-sequence (hydrogen-burning) star of spectral type B and luminosity class V. These stars have from 2 to 16 times the mass of the Sun and surface temperatures between 10,000 and 30,000 K. B-type stars ...

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 B1 V. It has a

luminosity Luminosity is an absolute measure of radiated electromagnetic power (light), the radiant power emitted by a light-emitting object over time. In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a st ...

of 9,120 Suns, consistent with an isochronal age of 5 million years and an estimated mass of 11

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. The radius is about 6.6 times that of the Sun. It 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 26,530 in its outer atmosphere. Omega¹ Scorpii is a β Cephei star that undergoes non-radial pulsations at a rate of 15 cycles per day. This is causing the surface temperature to fluctuate between 28,300 K and 22,600 K along the equator. The star is spinning rapidly 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 105 km/s and an estimated rotation period of 14^h.4. The poles of the star are inclined by around 60° to the line-of-sight from the

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 ...

Names

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 ...

, 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 twins who flee their parents into the sky and become the pair of stars Omega¹ and Omega² Scorpii. The girl, who is called Piri-ere-ua "Inseparable", keeps tight hold of her brother, who is not named.Johannes Carl Andersen (1931) ''Myths and Legends of the Polynesians''. 1995 Dover reprint, p.399–400. (The IAU used a version of this story from Tahiti to name Mu² Scorpii.)

References

External links

* {{Stars of Scorpius, state=collapsed B-type main-sequence stars Scorpius (constellation) Double stars Upper Scorpius Scorpii, Omega-1 Scorpii, 09 78933 5993 Piri-ere-ua 144470 Durchmusterung objects