Omega Carinae, Latinized from ω Carinae, 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

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 ...

Carina. With a

declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the ...

greater than 70 degrees south of the celestial equator, it is the most southerly of the bright stars of Carina (third-magnitude or brighter), and it is part of a southern asterism known as the

Diamond Cross Carina ( ) is a constellation in the southern sky. Its name is Latin for the keel of a ship, and it was the southern foundation of the larger constellation of Argo Navis (the ship ''Argo'') until it was divided into three pieces, the other two be ...

. This star has an apparent visual magnitude of 3.3 and is located at a distance of about 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 ...

Properties

Omega Carinae has 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 B8 IIIe, which places it in the category of

Be star Be stars are a heterogeneous set of stars with B spectral types and emission lines. A narrower definition, sometimes referred to as ''classical Be stars'', is a non-supergiant B star whose spectrum has, or had at some time, one or more Balmer e ...

s, that display emission lines of hydrogen their

spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors i ...

. Omega Carinae is a shell star, having a circumstellar disk of gas surrounding its equator. The luminosity class of III indicates it has

evolved 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 t ...

into a giant star, having exhausted the hydrogen at its core and left the

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 ...

. The

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 in its outer envelope is what gives this star the blue-white hue that is characteristic of B-type stars. This star is rotating 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 , which gives a lower limit to the star's

azimuth An azimuth (; from ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north. Mathematicall ...

al velocity along the equator. The critical equatorial velocity, at which the star would begin to break up, is . The star's axis of rotation is inclined by an estimated angle of 70.8° to the line of sight from the Earth. In the next 7500 years, the south Celestial pole will pass close to this star (AD 5800) and then

I Carinae The Bayer designations i Carinae and I Carinae are distinct (lower and upper case i) and refer to stars/star systems of apparent magnitude 3.96 and 3.99 respectively. *for i Carinae, see HD 79447 *for I Carinae, see HR 4102 I Carinae is ...

In culture

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 '' Southern Boat'', refers to an asterism consisting of ω Carinae,

V337 Carinae V337 Carinae (V337 Car, q Carinae) is a K-type bright giant star in the constellation of Carina. It is an irregular variable and has an apparent visual magnitude which varies between 3.36 and 3.44. V337 has a spectral cla ...

, PP Carinae, θ Carinae and β Carinae . Consequently, ω Carinae itself is known as (, en, the Fourth Star of Southern Boat.)AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 28 日
/ref>

References

External links

{{DEFAULTSORT:Omega Carinae Carinae, Omega B-type giants Carina (constellation) 050099 089080 4037 PD-69 1178 Be stars