Ain

Authors: Susanne M Hoffmann, Youla Azkarrula

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Ain - profile card (CC BY Sadegh Faghanpour for IAU-WGSN).

Ain

Asterism Info
Native	عين
Romanisation	Ayn
IPA	/ʕajn/
Translation	Eye
Position (2000)
Right ascension	67.15416773
Declination	19.18043421
Area	0 sq. deg.
Stars
Bright stars	1
Bayer/Flamsteed stars	1
Stars brighter than 3.00m	0
Brightest star	Ain (3.53m)
exoplanets	1 Amateru
Taxonomy
category of asterism	IAU-Star Name
IAU- constellations	Tau

Ain is a modern star name adopted by the International Astronomical Union in the IAU-Catalog of Star Names (IAU-CSN). Its origin is Arabic. It is the name of HIP 20889 (ε Tau, HR 1409) in constellation Tau.

Etymology and History

Kunitzsch and Smart (2006) think, the name is an abbreviation of the scholarly Arabic in mediaeval times, name ain al-thaur, "the Bull's Eye", for α Tau which was applied to ε Tau in recent times. However, Ptolemy had α Tau the southern eye, and ε Tau on the northern eye.

Ptolemy's Almagest (~135 CE)

id	Greek (Heiberg 1898)	English (Toomer 1984)	ident.
	Ταύρου ἀστερισμός	Constellation of Taurus
14	ὁ λαμπρὸς τῶν Ῥάδων ἐπὶ τοῦ νοτίου ὀφθαλμοῦ ὑπόκιρρος	The stars in the face, called 'the Hyades': the bright star of the Hyades, the reddish one on the southern eye	α Tau
15	ὁ λοιπὸς καὶ ἐπὶ τοῦ βορεύου ὀφθαλμοῦ	The stars in the face, called 'the Hyades': the remaining one, on the northern eye	ε Tau

Arabic translation

14	...	النجوم في الوجه، تسمى ”الهياديس“: النجم الساطع من الهياديس، النجم المحمر في العين الجنوبية		α Tau
15	...	النجوم في الوجه، تسمى ”الهياديس“: النجمة المتبقية، على العين الشمالية		ε Tau

The face of Taurus, the Bull, consists of two eyes, nostrils and other stars in the Hyadres star cluster. So, the name "Eye" can be a direct translation from Ancient Greek to Arabic.

IAU Working Group on Star Names

The name was adopted by the IAU WGSN on 2015/12/15. The star is a yellow giant with a confirmed exoplanet which was named simultaneously with the star (Amateru).

• 
  Ain - profile card (CC BY Sadegh Faghanpour for IAU-WGSN).
• 
  Ain - stickfigure (CC BY Sadegh Faghanpour for IAU-WGSN).
• 
  Ain's planet Amateru - profile card (CC BY Sadegh Faghanpour for IAU-WGSN).

Weblinks

• Website of the IAU WGSN: https://exopla.net/

Reference

• References (general)
• Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub.