The system consists of a spectroscopic binary pair designated Omicron Persei A and a third companion Omicron Persei B.[9] A's two components are themselves designated Omicron Persei Aa (officially named Atik/ˈeɪtɪk/, the traditional name of the system)[10][11] and Ab.
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).[12]
It bore the traditional name Atik (also Ati, Al Atik), Arabic for "the shoulder". Some sources attribute the name Atik to the nearby, brighter star Zeta Persei.[13][14] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[15] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[16] 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.[11]
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 33 R☉, the exact value depending on the inclination. The primary is approximately one magnitude brighter than the secondary at visual wavelengths.[5] The binary pair forms a rotating ellipsoidal variable star, which varies in brightness from visual magnitude 3.79 to 3.88 during the orbital period.[20]
Omicron Persei lies just north of the open clusterIC 348, but is not catalogued as a member. Both IC 348 and Omicron Persei belong to the Perseus OB2 association.[21]
^ abcDucati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
^ abcdefghiStickland, D. J.; Lloyd, C. (1998). "Spectroscopic binary orbits from ultraviolet radial velocities. Paper 28: Omicron Persei". The Observatory. 118: 138. Bibcode:1998Obs...118..138S.
^Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
^ abcdefLyubimkov, L. S.; Rachkovskaya, T. M.; Rostopchin, S. I.; Tarasov, A. E. (1997). "The binary system o per: Orbital elements, component parameters, and helium abundance". Astronomy Reports. 41 (5): 630. Bibcode:1997ARep...41..630L.
^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. ISBN978-1-931559-44-7.
^Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
^Mullaney, James, and Tirion, Wil (2009). The Cambridge Double Star Atlas, Chart 7. University Press, Cambridge. ISBN978-0-521-49343-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
^"omi Per". The International Variable Star Index. AAVSO. Retrieved 18 December 2022.
^Stelzer, B.; Preibisch, T.; Alexander, F.; Mucciarelli, P.; Flaccomio, E.; Micela, G.; Sciortino, S. (2012). "X-ray view of IC 348 in the light of an updated cluster census". Astronomy and Astrophysics. 537: A135. arXiv:1111.4420. Bibcode:2012A&A...537A.135S. doi:10.1051/0004-6361/201118118.