Chi Tauri, Latinised from χ Tauri, is a

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 speak ...

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 ...

of Taurus.

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 made by 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 ...

'' spacecraft put it at a distance of about from Earth. The primary component has an apparent magnitude of about 5.4, meaning it is visible with the naked eye. The main component of the system is Chi Tauri A. It is a B-type main-sequence star. Its mass is 2.6 times that of the Sun and its surface glows with 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 . It may be 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 ...

itself, as suggested from astrometric data from ''

'', although no orbit could be derived. The secondary component of the system is Chi Tauri B, separated about 19″ from Chi Tauri A. It was thought to be a post- T Tauri star from its unusual spectrum, but later studies ruled this out. It is a double-lined

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 ...

—the two stars are not resolved but their spectra have periodic

Doppler shift The Doppler effect or Doppler shift (or simply Doppler, when in context) is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who d ...

s indicating orbital motion. The two stars are an F-type star and a G-type star, respectively, and are designated Ba and Bb. The

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 Chi Tauri B has a slow drift indicating the presence of another star in the system. Designated Chi Tauri Bc, this massive object is too dim to be detected, but it appears in Chi Tauri B's spectrum as an infrared excess. Because of this infrared excess, this unseen component is thought to be a pair of K-type main-sequence stars both with masses 70% of the Sun's. The stars within the system appear to be dynamically interacting.

Naming

*With φ, κ¹, κ² and υ, it composed the Arabic were the Arabs' ''Al Kalbain'', the Two Dogs. According to the catalogue of stars in the ''Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars'', ''Al Kalbain'' were the title for five stars: φ as ''Alkalbain I'', this star (χ) as ''Alkalbain II'', κ¹ as ''Alkalbain III'', κ² as ''Alkalbain IV'' and υ as ''Alkalbain V''. *In Chinese, (), meaning '' Whetstone'', refers to an asterism consisting of χ Tauri, ψ Tauri, 44 Tauri and φ Tauri. Consequently, the Chinese name for χ Tauri itself is (, en, the Third Star of Whetstone).

References

{{DEFAULTSORT:Chi Tauri B-type main-sequence stars F-type main-sequence stars Spectroscopic binaries 5 Taurus (constellation) Tauri, Chi Durchmusterung objects Tauri, 059 027638 020430

1369 Year 1369 ( MCCCLXIX) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. Events January–December * February – Vladislav I of Wallachia liberates Vidin from the Hungarians, resul ...