The system consists of a binary star (Zeta Piscium A) and a triple star system (BC), the latter consisting of a spectroscopic binary (B) and a single star (C). A's two components are themselves designated Zeta Piscium Aa (officially named Revati/ˈreɪvəti/)[7] and Ab; B's two components as Ba and Bb.
As the star system is 0.21° south of the ecliptic,[8] it can be eclipsed (occulted) by the moon, when close to or at one of its two nodes of its orbit;[9] and is eclipsed by the sun from about 8-10 April.[10]
Nomenclature
ζ Piscium (Latinised to Zeta Piscium) is the system's Bayer designation. The designations of the three constituents as Zeta Piscium A, B and C, and those of A's and B's components - Zeta Piscium Aa, Ab, Ba and Bb - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[11]
The system is identified with Revati (Sanskrit: रेवती, romanized: rēvatī, Sanskrit pronunciation:[ˈɽeːʋɐt̪iː]), one of the Indian nakshatra (lunar mansions). In 2016, the IAU organized a Working Group on Star Names (WGSN)[12] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[13] It approved the name Revati for the constituent Zeta Piscium A on 30 June 2017 and it is now so included in the List of IAU-approved Star Names.[7] Where a component letter is not explicitly listed, the WGSN says that the name should be understood to be attributed to the brightest component by visual brightness (component Aa in this case).[14]
The secondary, Zeta Piscium B, is a spectroscopic binary with a period of 9.075 days and an eccentricity of 0.04. Together, components Ba and Bb have a combined visual magnitude of 6.43 and lie at an angular separation of 22.9 arcseconds from the primary. They are a F-typemain sequence star and a G-type main sequence star, respectively.
The tertiary and fifth component, Zeta Piscium C, is a magnitude 12.2 star at an angular separation 1.0 arc seconds from component B.[2]
Together the star system has an apparent magnitude of +4.9.[8]
^ abJohn Pratt's stars re-publication by Dr J.P. Pratt (Doctor of Astronomy, University of Arizona) of sidereal coordinate data. Note: possibly a non-book published source.
^Meyer, C.; et al. (1995), "Observations of lunar occultations at Observatoire de la Cote d'Azur", Astronomy and Astrophysics Supplement, 110: 107, Bibcode:1995A&AS..110..107M.
^In the Sky Earth astronomy reference utility showing the ecliptic and relevant date as at J2000 - present.
^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].
