Iota Aurigae (ι Aurigae, abbreviated Iota Aur, ι Aur), officially named Hassaleh , is a

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 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 origins of the e ...

of Auriga. It has an apparent visual magnitude of 2.7, which is bright enough to be readily visible to the naked eye.

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 give a distance estimate of roughly from the Sun.

Nomenclature

''ι Aurigae'' ( Latinised to ''Iota Aurigae'') 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. ...

. It bore the traditional name ''Al Kab'', short for ''Kabdhilinan'' , from the Arabic ʿAbd al-Raḥmān ibn ʿUmar al-Ṣūfī
صور الكواكب الثابتة
('' Book of Fixed Stars''). Manuscript from the National Library of France. "the ankleTranslation of the Arabic word كعب to English
on the Almaany dictionaries website. of the rein holder (charioteer)". Under the name ''Alkab'', this star is a marker on the

astrolabe An astrolabe ( grc, ἀστρολάβος ; ar, ٱلأَسْطُرلاب ; persian, ستاره‌یاب ) is an ancient astronomical instrument that was a handheld model of the universe. Its various functions also make it an elaborate inclin ...

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 wa ...

in his '' Treatise on the Astrolabe'' in 1391. It bore the novel name ''Hassaleh'' in Antonín Bečvář'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 constellation in Chinese astronomy. Introduction A five-star Chinese constellation equivalent to Auriga minus δ Aur ( Delta Aurigae). Also known in Japanese as Gosha (Five Chariots; 五車). Stars * ...

) in Chinese.

Properties

At Iota Aurigae's distance, extinction from interstellar dust is causing a magnitude reduction of about 0.6. Examination of the spectrum 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 grati ...

of K3 II, with the luminosity class of 'II' indicating this is a category of evolved star known as a bright giant. 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 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, although this variability remains unconfirmed.

Unconfirmed substellar companions

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

Santorini Santorini ( el, Σαντορίνη, ), officially Thira (Greek: Θήρα ) and classical Greek Thera (English pronunciation ), is an island in the southern Aegean Sea, about 200 km (120 mi) southeast from the Greek mainland. It is the ...

, 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 fo ...

s orbiting Iota Aurigae in 2:1 resonance. Such companions would be brown dwarfs with orbital periods of approximately 2 and 4 years. No minimum mass for the candidates was provided. So far the detection has not been confirmed, though Hekker et al. (2008) listed significant

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 ...

variations at periods of 767 and 1586 days.

References

External links

HR 1577

Image Iota AurigaeExtreme Solar Systems Abstracts
{{DEFAULTSORT:Iota Aurigae 031398 023015 Aurigae, Iota Auriga (constellation) K-type bright giants Hassaleh Hypothetical planetary systems Aurigae, 03

1577 __NOTOC__ Year 1577 ( MDLXXVII) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar. Events January–June * January 9 – The second Union of Brussels is formed, first without the P ...

BD+32 0855