Omega Carinae, Latinized from ω Carinae, is a star in the constellation

Carina Carina may refer to: Places Australia * Carina, Queensland, a suburb in Brisbane * Carina Heights, Queensland, a suburb in Brisbane * Carina, Victoria, a locality in Mildura Serbia * Carina, Osečina, a village in the Kolubara District ...

. With a declination greater than 70 degrees south of the

celestial equator The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth. This plane of reference bases the equatorial coordinate system. In other words, the celestial equator is an abstract proj ...

, 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 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 3.3 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 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 line A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identi ...

s 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 ...

. Omega Carinae is a

shell star A shell star is a star having a spectrum that shows extremely broad absorption lines, plus some very narrow absorption lines. They typically also show some emission lines, usually from the Balmer series but occasionally of other lines. The broa ...

, having a circumstellar disk of gas surrounding its equator. The

luminosity class 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 the ...

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 ...

into a

giant star A giant star is a star with substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Press ...

, having exhausted the hydrogen at its core and left the main sequence. The effective 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 bulg ...

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. Mathematical ...

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.

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 ...

, (), 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 p Carinae is the Bayer designation of a star in the southern constellation of Carina. It has the variable star designation PP Carinae and, at an apparent visual magnitude of +3.3, is readily visible to the naked eye from the southern hem ...

, 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