Zeta Piscium

Zeta Piscium (Zeta Psc, ζ Piscium, ζ Psc) is an optical and spectroscopic binary system, with three components — Zeta Piscium A, Zeta Piscium B and Zeta Piscium C. Zeta Piscium B and C are spectroscopic binaries with each other, and both are optical binaries with Zeta Piscium A. The separation between Zeta Piscium A and the B and C system is 23 arcsec.

• Zeta Piscium A, also known as HR 361, is the brighter optical component, with an apparent magnitude of +5.21 and absolute magnitude of +1.93. Zeta Piscium A is a subgiant with spectral class of A7IV, with 1.8 solar masses, and effective temperature of 7900K. Zeta Piscium A is located approximately 147.5 LY from the Sun.
• Zeta Piscium B, also known as HR 362 is an F7V dwarf with effective temperature of 6400K and 1.3 solar masses. It has an apparent magnitude of 6.44 and absolute magnitude of +2.55. It is located 195.2 LY from the Sun.
• Zeta Piscium C is a white dwarf companion to Zeta Piscium B.

Zeta Piscium A is also known as Zeta¹ Piscium (ζ¹ Psc, ζ¹ Piscium) and has the following position:^[1]

• Equatorial coordinates:
  • Right Ascension: 1^h 13^m 43.886^s
  • Declination: +7° 34' 31.13"

Zeta Piscium B is also known as Zeta² Piscium (ζ² Psc, ζ² Piscium) and has the following position:^[2]

• Equatorial coordinates:
  • Right Ascension: 1^h 13^m 45.311^s
  • Declination: +7° 34' 41.99"

Naming

In Chinese, 外屏 (Wài Píng), meaning Outer Fence, refers to an asterism consisting of refers to an asterism consisting of ζ Piscium, δ Piscium, ε Piscium, μ Piscium, ν Piscium, ξ Piscium and α Piscium. Consequently, ζ Piscium itself is known as 外屏三 (Wài Píng sān, English: the Third Star of Outer Fence.)^[3]

References

1. Frosty Drew Observatory & Sky Theatre — Zeta 1 Piscium
2. Frosty Drew Observatory & Sky Theatre — Zeta 2 Piscium
3. (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日