Kappa Velorum (κ Velorum, abbreviated Kappa Vel, κ Vel;
proper name Markeb
) is a
binary star
A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in wh ...
system in the southern
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 ...
of
Vela. The two components are designated Kappa Velorum A and B.
From
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, this system is located at a distance of roughly from the
Sun. The
apparent visual magnitude is 2.48,
[ making it readily visible to the naked eye in the southern hemisphere. It forms part of an asterism known as the False Cross along with ]Delta Velorum
Delta Velorum (δ Velorum, abbreviated Delta Vel, δ Vel) is a triple star system in the southern constellation of Vela, near the border with Carina, and is part of the False Cross. Based on parallax measurements, it is approxima ...
, Iota Carinae and Epsilon Carinae, so called because it is sometimes mistaken for the Southern Cross, causing errors in astronavigation
Celestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space (or on the surface o ...
.
Nomenclature
''κ Velorum'' ( Latinised to ''Kappa Velorum'') is the system'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. ...
. The designations of the two components as ''Kappa Velorum A'' and ''B'' derives from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star system
A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a '' star cluster'' or '' galaxy'', although, broadly speaki ...
s, and adopted by the International Astronomical Union (IAU).[ from the Arabic مركب, ''markab'' meaning "something to ride".][ to distinguish it from similarly named stars such as ]Alpha Pegasi
Alpha Pegasi (α Pegasi, abbreviated Alpha Peg, α Peg), formally named Markab , is the third-brightest star in the constellation of Pegasus and one of the four stars in the asterism known as the Great Square of Pegasus.
Properties
Alp ...
. In 2016, the IAU organized a Working Group on Star Names (WGSN)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 '' Celestial Earth God's Temple'', refers to an asterism consisting of Kappa Velorum, Gamma² Velorum, b Velorum and Delta Velorum
Delta Velorum (δ Velorum, abbreviated Delta Vel, δ Vel) is a triple star system in the southern constellation of Vela, near the border with Carina, and is part of the False Cross. Based on parallax measurements, it is approxima ...
. Consequently, Kappa Velorum itself is known as (), "the Fifth Star of Celestial Earth God's Temple".
Properties
Kappa Velorum is a spectroscopic binary
A binary star is a system of two star, stars that are gravity, gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separa ...
system consisting of a pair of stars that complete an orbit around each other with a period of 116.65 days and an eccentricity of 0.19. Because the individual stars have not been resolved, further details of the orbit have not yet been determined.[ The combined ]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 the pair is B2 IV,[ which matches the class of a B-type subgiant star that has exhausted the hydrogen at its core and begun to evolve into a giant. It has an estimated size of 6.9 times the Sun's radius.][
The system is only a couple of degrees from the south celestial pole of Mars, so it could therefore be considered the southern polar star of that planet. Due to precession of the equinoxes, it will be the closest bright star of note to the south celestial pole of Earth in the period surrounding 9000 AD.
]
Interstellar medium
Analysis of the spectrum of Kappa Velorum shows absorption lines due to the interstellar medium
In astronomy, the interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstella ...
between Earth and the star. Observation of these features over many years has shown that the lines vary in strength, probably caused by a small dense cloud extending 10²–10³ au moving across the line of sight.
References
External links
* "The path of the Southern Celestial Pole": The System of W. B. Yeats's A Visio
Diagram of the southern precession circle, showing Markeb as the South Pole Star in 9000 AD.
*
{{DEFAULTSORT:Kappa Velorum
Bayer objects, Velorum, Kappa
081188
045941
3734
Vela (constellation)
B-type subgiants
Spectroscopic binaries
Durchmusterung objects