Iota Aurigae is a

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

in the northern

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 first constellati ...

Auriga Auriga is a constellation in the northern celestial hemisphere. It is one of the 88 modern constellations; it was among the 48 constellations listed by the 2nd-century astronomer Ptolemy. Its name is Latin for '(the) charioteer', associating i ...

. Its name is a

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...

that is Latinized from ι Aurigae, abbreviated Iota Aur or ι Aur. The star has the official name Hassaleh, pronounced . It has an

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light ca ...

of 2.7, which is bright enough to be readily visible to the

naked eye Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnification, magnifying, Optical telescope#Light-gathering power, light-collecting optical instrument, such as a telescope or microsc ...

Parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

measurements give a distance estimate of roughly from the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

. It is drifting further away with a

radial velocity The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity ...

of +18 km/s.

Nomenclature

''ι Aurigae'' ( Latinised to ''Iota Aurigae'') is the star's

. It bore the traditional name ''Al Kab'', short for ''Kabdhilinan'' , from the

Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

ʿAbd al-Raḥmān ibn ʿUmar al-Ṣūfī
صور الكواكب الثابتة
(''

Book of Fixed Stars ''The Book of Fixed Stars'' ( ', literally ''The Book of the Shapes of Stars'') is an Astronomy, astronomical text written by Abd al-Rahman al-Sufi (Azophi) around 964. Following Graeco-Arabic translation movement, the translation movement in the ...

''). Manuscript from the National Library of France. "the

ankle The ankle, the talocrural region or the jumping bone (informal) is the area where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint. The ...

Translation of the Arabic word كعب to English
on the Almaany dictionaries website. of the

rein Reins are used to direct a horse (or other animal) when riding or driving. They are attached to a bridle's bit or noseband and are made of leather, nylon, or other materials. Reins are used to give subtle commands or cues—also known as r ...

holder (charioteer)". Under the name ''Alkab'', this star is a marker on the

astrolabe An astrolabe (; ; ) is an astronomy, astronomical list of astronomical instruments, instrument dating to ancient times. It serves as a star chart and Model#Physical model, physical model of the visible celestial sphere, half-dome of the sky. It ...

described by

Geoffrey Chaucer Geoffrey Chaucer ( ; – 25 October 1400) was an English poet, author, and civil servant best known for ''The Canterbury Tales''. He has been called the "father of English literature", or, alternatively, the "father of English poetry". He w ...

in his ''

Treatise on the Astrolabe ''A Treatise on the Astrolabe'' is a medieval instruction manual on the astrolabe by Geoffrey Chaucer. It was completed in 1391. It describes both the form and the proper use of the instrument, and stands out as a prose technical work from a wr ...

'' in 1391. It bore the novel name ''Hassaleh'' in

Antonín Bečvář Antonín Bečvář (; 10 June 1901 – 10 January 1965) was a Czechoslovak astronomer. Biography He was born and died in Stará Boleslav. Among his chief achievements is the foundation of the Skalnaté Pleso Observatory and the discovery of the ...

's 1951 atlas. The origin and meaning of the name have not been discovered despite extensive search, and no connection to any language has been discovered. The

IAU 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)has approved the proper name ''Hassaleh'' for this star. It is known as 五車一 (the First Star of the

Five Chariots Five Chariots (五車, pinyin: Wǔ Ju) is a Chinese constellation equivalent to Auriga, minus Delta Aurigae. It is known in Japanese as Gosha (五車). Stars * Iota Aurigae * Alpha Aurigae * Beta Aurigae * Theta Aurigae * Gamma Aurigae Char ...

) in

Chinese Chinese may refer to: * Something related to China * Chinese people, people identified with China, through nationality, citizenship, and/or ethnicity **Han Chinese, East Asian ethnic group native to China. **'' Zhonghua minzu'', the supra-ethnic ...

Properties

At Iota Aurigae's distance,

extinction Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

from interstellar dust is causing a magnitude reduction of about 0.6. Examination of the

spectrum A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...

yields 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 gratin ...

of K3 II–III, with the

luminosity class 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 gratin ...

of 'II–III' indicating this is a

evolved Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...

hybrid giant star. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. The

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 the outer envelope is 4,160 K, which is cooler than the Sun's effective temperature and gives Iota Aurigae the orange hue of a K-type star. It is a weak

X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

emitter with an X-ray luminosity of about . This emission is most likely coming from transient loops of plasma in Iota Aurigae's outer atmosphere, which have a temperature of around . This is a suspected

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...

. During the ''Extreme Solar Systems'' conference held on June 25–29, 2007, in

Santorini Santorini (, ), officially Thira (, ) or Thera, is a Greek island in the southern Aegean Sea, about southeast from the mainland. It is the largest island of a small, circular archipelago formed by the Santorini caldera. It is the southern ...

, Greece, Reffert et al. announced the detection of two

substellar object A substellar object, sometimes called a substar, is an astronomical object, the mass of which is smaller than the smallest mass at which hydrogen fusion can be sustained (approximately 0.08 solar masses). This definition includes brown dwarfs and f ...

s orbiting Iota Aurigae in 2:1

resonance Resonance is a phenomenon that occurs when an object or system is subjected to an external force or vibration whose frequency matches a resonant frequency (or resonance frequency) of the system, defined as a frequency that generates a maximu ...

. Such companions would be

brown dwarf Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main sequence, main-sequence stars. Their mass is approximately 13 to 80 Jupiter mass, times that of Jupiter ()not big en ...

s with

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

s of approximately 2 and 4 years. No minimum mass for the candidates was provided. As of 2008, the detection has not been confirmed, though Hekker et al. (2008) listed significant

variations at periods of 767 and 1586 days. It may instead be an oscillating star undergoing non-radial pulsations with a period of about four years.

References

External links

HR 1577

Image Iota AurigaeExtreme Solar Systems Abstracts
{{DEFAULTSORT:Iota Aurigae K-type bright giants Astronomical X-ray sources Pulsating variables Hypothetical planetary systems Auriga Aurigae, Iota

1577 Year 1577 ( MDLXXVII) was a common year starting on Tuesday of the Julian calendar. Events January–March * January 9 – The second Union of Brussels is formed, first without the Protestant counties of Holland and Zeeland (wh ...

Aurigae, 03 031398 023015 Hassaleh BD+32 0855