Theta Columbae, also named Elkurud ,
is a solitary
[ ]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 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 Columba
Columba or Colmcille; gd, Calum Cille; gv, Colum Keeilley; non, Kolban or at least partly reinterpreted as (7 December 521 – 9 June 597 AD) was an Irish abbot and missionary evangelist credited with spreading Christianity in what is toda ...
. It is faintly visible to the naked eye, having an apparent visual magnitude of 5.02.[ Based upon ]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 taken during the Hipparcos
''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial obj ...
mission, it is roughly distant from the Sun.[ At its present distance, the visual magnitude of the star is reduced by an interstellar extinction factor of 0.11.][ It is currently moving away from the Sun with a ]radial velocity
The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...
of 45.3 km/s.[ The star made its closest approach about 4.7 million years ago when it underwent perihelion passage at a distance of .][
This is an evolving B-type subgiant 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 grati ...
of B8 IV,[ having recently 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 ...
.[ It 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 249 km/s.[ The star has an estimated four times the ]mass of the Sun
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 ...
.[ It radiates 472 times the solar luminosity from its outer atmosphere at 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 9,916 K.[
]
Nomenclature
''θ Columbae'', Latinised to ''Theta Columbae'', is the star'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. ...
.
Early Arab poets referred to a number of anonymous stars as الفرود ''al-furūd'', "the solitary ones". Later Arabian astronomers attempted to identify this name with particular stars, principally in the modern constellations Centaurus and Colomba. Allen (1899) noted the accepted etymology but suggested that ''al-furūd'' might have been an old transcriber's error for القرود ''al-qurūd'' "the apes", which he rendered "Al Ḳurūd",[ though this suggested has not received scholarly support.][
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)Zeta Canis Majoris
Zeta Canis Majoris, or ζ Canis Majoris, also named Furud , is a binary star system in the southern constellation of Canis Major. This system has an apparent visual magnitude of +3.0, making it one of the brighter stars in the constella ...
.)
In 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 ''Grandson
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
'', refers to an asterism consisting of Theta Columbae and Kappa Columbae. Consequently, Theta Columbae itself is known as (, en, the Second Star of Grandson).AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 16 日
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References
{{DEFAULTSORT:Theta Columbae
B-type subgiants
Columba (constellation)
Columbae, Theta
Durchmusterung objects
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