Eta Piscium

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Eta Piscium
Location of η Piscium (circled)
Observation data
ICRS
)
Constellation Pisces
Right ascension 01h 31m 29.01026s[1]
Declination +15° 20′ 44.9685″[1]
Apparent magnitude (V) +3.611[2] (3.83 + 7.51)[3]
Characteristics
Spectral type G7 IIIa[4]
U−B color index +0.730[2]
B−V color index +0.976[2]
Variable type
γ Cas
Distance
350 ± 30 ly
(107 ± 8 pc)
Absolute magnitude (MV)−1.52[6]
Argument of periastron
(ω)
(secondary)		86.9±4.0°
Details
Myr
HR 437, SAO 92484, WDS J01315+1521AB[9]
Database references
SIMBADdata

Eta Piscium (η Piscium, abbreviated Eta Psc, η Psc) is a

mas as seen from Earth,[1] it is located roughly 350 light-years distant from the Sun in the thin disk population of the Milky Way.[5]

The two components are designated Eta Piscium A (formally named Alpherg /ˈælfɜːrɡ/, the traditional name of the system)[10] and B.

Nomenclature

η Piscium (Latinised to Eta Piscium) is the system's Bayer designation. The designations of the two constituents as Eta Piscium A and B 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 bore the traditional names Al Pherg (in this context meaning the emptying) and Kullat Nunu. At the time that the

multiple systems.[14] It approved the name Alpherg for the component Eta Piscium A on 1 June 2018 (for its official List).[10]

In

Chinese name for Eta Piscium itself is 右更二 (Yòu Gèng èr, English: the Second Star of Official in Charge of the Pasturing.)[15]

Properties

At its present distance, the visual magnitude of the system is diminished by an

interstellar dust
.

This system's binary nature was discovered in 1878 by an amateur astronomer,

arc seconds, and an eccentricity
of 0.47.

The primary, component A, is an

G-type giant star with a stellar classification of G7 IIIa.[4] It has a weak magnetic field with a strength of 0.4±0.2 G,[8] and is a Gamma Cassiopeiae variable.[7] The companion, component B, is a magnitude 7.51 star.[3]

References

  1. ^
    S2CID 18759600
    .
  2. ^
    Bibcode:1985A&AS...59..461O
    .
  3. ^
    S2CID 14878976
    .
  4. ^
    doi:10.1086/191373
    .
  5. ^
    S2CID 119289111
    , A84.
  6. S2CID 119257644
    .
  7. ^
    doi:10.1002/asna.200911250
    .
  8. ^
    S2CID 118504829
    , A90.
  9. ^ "eta Psc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-30.
  10. ^ a b "Naming Stars". IAU.org. Retrieved 18 June 2018.
  11. arXiv:1012.0707 [astro-ph.SR
    ].
  12. ISBN 0-486-21079-0
  13. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  14. ^ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  15. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日 Archived 2016-03-03 at the Wayback Machine

External links

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