Phi Tauri (φ Tauri) is a solitary, orange-hued

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 zodiac

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. It has an apparent visual magnitude of +4.96, which indicates the star is faintly visible to the naked eye. 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 objects ...

shift of 10.16

mas Mas, Más or MAS may refer to: Film and TV * Más y Menos, fictional superhero characters, from the Teen Titans animated television series * Más (Breaking Bad), "Más" (''Breaking Bad''), a season three episode of ''Breaking Bad'' Songs * Más ( ...

as seen from Earth, it is located roughly 321

light year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s distant from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.27 due to interstellar dust. This is an evolved, K-type giant 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 K1 III, currently (97% probability) on the red giant branch. It has an estimated 1.36 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 ...

and has expanded to 19 times the Sun's radius. At the age of roughly five billion years, it is radiating 131 times the Sun's luminosity from its inflated

photosphere The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it ...

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 4,479 K. Phi Tauri has a magnitude 7.51 visual companion located at an

angular separation Angular distance \theta (also known as angular separation, apparent distance, or apparent separation) is the angle between the two sightlines, or between two point objects as viewed from an observer. Angular distance appears in mathematics (in pa ...

of 48.80 arc seconds along a position angle of 258°, as of 2015. The pair form a yellow and blue double that is visible in small telescopes. A fainter, magnitude 12.27 companion lies at a separation of 118.10 arc seconds along a position angle of 25°, as of 2001.

Naming

*With κ¹, κ², υ and χ, 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 : this star (φ) as ''Alkalbain I'', 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 φ Tauri, ψ Tauri, 44 Tauri and χ Tauri. Consequently, the Chinese name for φ Tauri itself is (, en, the Fourth Star of Whetstone.).AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 22 日
/ref>

References

{{DEFAULTSORT:Phi Tauri K-type giants Double stars Tauri, Phi Taurus (constellation) Durchmusterung objects Tauri, 052 027382 020250

1348 Year 1348 ( MCCCXLVIII) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar, the 1348th year of the Common Era (CE) and ''Anno Domini'' (AD) designations, the 348th year of the 2nd millennium, the 48t ...