Omicron Persei (ο Persei, abbreviated Omicron Per, ο Per) is a triple star system in the constellation of Perseus.
From parallax measurements taken during the Hipparcos mission it is approximately 1,100 light-years (330 parsecs) from the Sun.
The system consists of a spectroscopic binary pair designated Omicron Persei A and a third companion Omicron Persei B.  A's two components are themselves designated Omicron Persei Aa (officially named Atik , the traditional name of the system) and Ab.
Nomenclature
thumb|left|ο Persei in optical light ο Persei (Latinised to Omicron Persei) is the system's Bayer designation.
The designations of the two constituents as Omicron Persei A and B, and those of A's components - Omicron Persei Aa and Ab - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).
It bore the traditional name Atik (also Ati, Al Atik), Arabic for "the shoulder".
Some sources, including a planetarium software package, an atlas, and a web siteYour Sky Object Catalogue: Named Stars attribute the name Atik to the nearby, brighter star Zeta Persei.
In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars.
The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.
It approved the name Atik for the component Omicron Persei A on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.
In Chinese,  (), meaning Rolled Tongue, refers to an asterism consisting of Omicron Persei, Nu Persei, Epsilon Persei, Xi Persei, Zeta Persei and 40 Persei. 中國星座神話
, written by 陳久金.
Published by 台灣書房出版有限公司, 2005, .
Consequently, the Chinese name for Omicron Persei itself is  (), "the Fifth Star of Rolled Tongue". 香港太空館
- 研究資源 - 亮星中英對照表 , Hong Kong Space Museum.
Accessed on line November 23, 2010.
Namesake
USS Atik was a ship of the United States Navy.
Properties
Omicron Persei A is a spectroscopic binary consisting of a spectral type B1 giant and a type B2 dwarf orbiting each other every 4.4 days.
The orbit is near-circular although its inclination is not precisely known.
The two stars are separated by approximately , the exact value depending on the inclination.
The primary is approximately one magnitude brighter than the secondary at visual wavelengths.
Omicron Persei lies just north of the open cluster IC 348, but is not catalogued as a member.
Both IC 348 and Omicron Persei belong to the Perseus OB2 association.
References
External links
Atik
