Beta Canum Venaticorum (β Canum Venaticorum, abbreviated Beta CVn, β CVn), also named Chara , is a

G-type main-sequence star A G-type main-sequence star (Spectral type: G-V), also often, and imprecisely called a yellow dwarf, or G star, is a main-sequence star (luminosity class V) of spectral type G. Such a star has about 0.9 to 1.1 solar masses and an effective tem ...

in the northern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the earliest constellation ...

Canes Venatici Canes Venatici () is one of the 88 constellations designated by the International Astronomical Union (IAU). It is a small northern constellation that was created by Johannes Hevelius in the 17th century. Its name is Latin for 'hunting dogs', and ...

. At 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 4.25, it is the second-brightest star in the constellation. Based upon an annual

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 object ...

shift of , this star is distant 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 ...

. Along with the brighter star

Cor Caroli Cor Caroli is a binary star designated Alpha Canum Venaticorum or α Canum Venaticorum. The International Astronomical Union uses the name "Cor Caroli" specifically for the brighter star of the binary. Alpha Canum Venaticorum is the brig ...

, the pair form the "southern dog" in this constellation that represents

hunting dog A hunting dog is a canine that hunts with or for hunters. There are several different types of hunting dog developed for various tasks and purposes. The major categories of hunting dog include hounds, terriers, dachshunds, cur type dogs, and gu ...

Nomenclature

''β Canum Venaticorum'' ( Latinised to ''Beta Canum Venaticorum'') 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 ...

. The traditional name ''Chara'' was originally applied to the "southern dog", but it later became used specifically to refer to Beta Canum Venaticorum. Chara ''(χαρά)'' means 'joy' in

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

. In 2016, the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

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) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included ''Chara'' for this star. In Chinese, (), meaning ''

Imperial Guards An imperial guard or palace guard is a special group of troops (or a member thereof) of an empire, typically closely associated directly with the Emperor or Empress. Usually these troops embody a more elite status than other imperial forces, in ...

'', refers to an asterism consisting of Beta Canum Venaticorum, Alpha Canum Venaticorum, 10 Canum Venaticorum,

6 Canum Venaticorum 6 Canum Venaticorum is a single star in the northern constellation Canes Venatici, located 246 light years from the Sun. It is visible to the naked eye as a faint yellow-hued star with an apparent visual magnitude of +5.01. The star i ...

, 2 Canum Venaticorum, and 67 Ursae Majoris. Consequently, the

Chinese name Chinese names or Chinese personal names are names used by individuals from Greater China and other parts of the Chinese-speaking world throughout East and Southeast Asia (ESEA). In addition, many names used in Japan, Korea and Vietnam are ofte ...

for Beta Canum Venaticorum itself is (, en, the Fourth Star of Imperial Guards.)香港太空館 - 研究資源 - 亮星中英對照表
, Hong Kong Space Museum. Accessed on line November 23, 2010.

Observations

Beta CVn has a

stellar classification 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 G0 V, and so is a

. Since 1943, the

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 ...

of this star has served as one of the stable anchor points by which other stars are classified. The spectrum of this star shows a very weak

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 ...

of singly ionized calcium (Ca II) from the

chromosphere A chromosphere ("sphere of color") is the second layer of a star's atmosphere, located above the photosphere and below the solar transition region and corona. The term usually refers to the Sun's chromosphere, but not exclusively. In the ...

, making it a useful reference star for a reference spectrum to compare with other stars in a similar spectral category. (The Ca-II emission lines are readily accessible and can be used to measure the level of activity in a star's chromosphere.) Beta CVn is considered to be slightly metal-poor, which means it has a somewhat lower portion of elements heavier than

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic ta ...

when compared to the Sun. In terms of mass, age and evolutionary status, however, this star is very similar to the Sun. As a result, it has been called a

solar analog Solar-type star, solar analogs (also analogues), and solar twins are stars that are particularly similar to the Sun. The stellar classification is a hierarchy with solar twin being most like the Sun followed by solar analog and then solar-type ...

. It is about 3% less massive than the Sun, with a radius 12% larger than the Sun's and 15% greater luminosity. The components of this star's space velocity are = . In the past it was suggested that it may be a

spectroscopic binary 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 w ...

. However, further analysis of the data does not seem to bear that out. In addition, a 2005 search for a

brown dwarf Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most ...

in orbit around this star failed to discover any such companion, at least down to the sensitivity limit of the instrument used.

Habitability

In 2006, astronomer Margaret Turnbull labeled Beta CVn as the top stellar system candidate to search for

extraterrestrial life Extraterrestrial life, colloquially referred to as alien life, is life that may occur outside Earth and which did not originate on Earth. No extraterrestrial life has yet been conclusively detected, although efforts are underway. Such life might ...

forms. Because of its solar-type properties, astrobiologists have listed it among the most astrobiologically interesting stars within 10 parsecs of the Sun. However, as of 2009, this star is not known to host planets.

References

External links

* * {{DEFAULTSORT:Beta Canum Venaticorum Canes Venatici Canum Venaticorum, Beta G-type main-sequence stars Canum Venaticorum, Beta Chara Canum_Venaticorum, 08 061317 109358 4785 Durchmusterung objects

Nomenclature

Observations

Habitability

See also

References

External links