Movatterモバイル変換


[0]ホーム

URL:


Jump to content
WikipediaThe Free Encyclopedia
Search

Eta Piscium

From Wikipedia, the free encyclopedia
Binary star system in the constellation Pisces
Eta Piscium
Location of η Piscium (circled)
Observation data
Epoch J2000      Equinox J2000
ConstellationPisces
Right ascension01h 31m 29.01026s[1]
Declination+15° 20′ 44.9685″[1]
Apparent magnitude (V)+3.611[2](3.83 + 7.51)[3]
Characteristics
Spectral typeG7 IIIa[4]
U−Bcolor index+0.730[2]
B−Vcolor index+0.976[2]
Variable typeγ Cas
Astrometry
Radial velocity (Rv)13.60±0.42[5] km/s
Proper motion (μ)RA: +27.14[1]mas/yr
Dec.: −2.64[1]mas/yr
Parallax (π)9.33±0.72 mas[1]
Distance350 ± 30 ly
(107 ± 8 pc)
Absolute magnitude (MV)−1.52[6]
Orbit[7]
Period (P)850.5±66.5 yr
Semi-major axis (a)1.228±0.144
Eccentricity (e)0.469±0.053
Inclination (i)58.5±2.5°
Longitude of the node (Ω)32.8±2.0°
Periastronepoch (T)2040.3±66.9
Argument of periastron (ω)
(secondary)
86.9±4.0°
Details[5]
η Psc A
Mass3.78±0.16 M
Radius26.48±2.15 R
Luminosity457 L
Surface gravity (log g)2.20±0.14 cgs
Temperature4,937±40 K
Metallicity[Fe/H]−0.13±0.06 dex
Rotational velocity (v sin i)8.4[8] km/s
Age220±30 Myr
Other designations
Alpherg,η Psc,99 Piscium,BD+14°231,FK5 50,HD 9270,HIP 7097,HR 437,SAO 92484,WDS J01315+1521AB[9]
Database references
SIMBADdata

Eta Piscium (η Piscium, abbreviatedEta Psc,η Psc) is abinary star and the brightest star in the equatorial-northern constellation ofPisces, with anapparent visual magnitude of +3.6.[2] Based upon a measured annualparallax shift of 9.33 mas as seen from Earth,[1] it is located roughly 350 light-years distant from theSun in thethin disk population of theMilky Way.[5]

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

Nomenclature

[edit]

η Piscium (Latinised toEta Piscium) is the system'sBayer designation. The designations of the two constituents asEta Piscium A andB derive from the convention used by the Washington Multiplicity Catalog (WMC) formultiple star systems, and adopted by theInternational Astronomical Union (IAU).[11]

The system bore the traditional namesAl Pherg (in this context meaning the emptying) andKullat Nunu. At the time that theSun at the March Equinox entered into Pisces having lay in Aries, the system was in the first ecliptic constellation of theNeo-Babylonians,Kullat NūnuNūnu being Babylonian for fish andKullat referring to either the bucket or the cord that binds the fish.[12] In 2016, the IAU organized aWorking Group on Star Names (WGSN)[13] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entiremultiple systems.[14] It approved the nameAlpherg for the component Eta Piscium A on 1 June 2018 (for its official List).[10]

InChinese,右更 (Yòu Gèng), meaningOfficial in Charge of the Pasturing, refers to anasterism consisting of Eta Piscium,Rho Piscium,Pi Piscium,Omicron Piscium and104 Piscium. Consequently, theChinese 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

[edit]

At its present distance, the visual magnitude of the system is diminished by anextinction factor of0.09±0.06 due tointerstellar dust.

This system's binary nature was discovered in 1878 by an amateur astronomer,S. W. Burnham.[7] It has anorbital period of roughly 850 years, asemimajor axis of 1.2 arc seconds, and aneccentricity of 0.47.

The primary, component A, is anevolved, magnitude 3.83[3]G-typegiant star with astellar classification of G7 IIIa.[4] It has a weakmagnetic field with a strength of0.4±0.2 G,[8] and is aGamma Cassiopeiae variable.[7] The companion, component B, is a magnitude 7.51 star.[3]

References

[edit]
  1. ^abcdefvan Leeuwen, F. (2007), "Validation of the new Hipparcos reduction",Astronomy and Astrophysics,474 (2):653–664,arXiv:0708.1752,Bibcode:2007A&A...474..653V,doi:10.1051/0004-6361:20078357,S2CID 18759600.
  2. ^abcdOja, T. (March 1985), "UBV photometry of stars whose positions are accurately known. II",Astronomy and Astrophysics Supplement Series,59:461–464,Bibcode:1985A&AS...59..461O.
  3. ^abcEggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems",Monthly Notices of the Royal Astronomical Society,389 (2):869–879,arXiv:0806.2878,Bibcode:2008MNRAS.389..869E,doi:10.1111/j.1365-2966.2008.13596.x,S2CID 14878976.
  4. ^abKeenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars",Astrophysical Journal Supplement Series,71: 245,Bibcode:1989ApJS...71..245K,doi:10.1086/191373.
  5. ^abcMaldonado, J.; et al. (June 2013), "The metallicity signature of evolved stars with planets",Astronomy & Astrophysics,554: 18,arXiv:1303.3418,Bibcode:2013A&A...554A..84M,doi:10.1051/0004-6361/201321082,S2CID 119289111, A84.
  6. ^Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation",Astronomy Letters,38 (5): 331,arXiv:1108.4971,Bibcode:2012AstL...38..331A,doi:10.1134/S1063773712050015,S2CID 119257644.
  7. ^abcCvetković, Z.; Novaković, B. (March 2010), "Eight new and three recalculated orbits for binaries",Astronomische Nachrichten,331 (3): 304,Bibcode:2010AN....331..304C,doi:10.1002/asna.200911250.
  8. ^abAurière, M.; Konstantinova-Antova, R.; Charbonnel, C.; Wade, G. A.; Tsvetkova, S.; Petit, P.; Dintrans, B.; Drake, N. A.; Decressin, T.; Lagarde, N.; Donati, J. F.; Roudier, T.; Lignières, F.; Schröder, K. P.; Landstreet, J. D.; Lèbre, A.; Weiss, W. W.; Zahn, J. P. (February 2015), "The magnetic fields at the surface of active single G-K giants",Astronomy & Astrophysics,574: 30,arXiv:1411.6230,Bibcode:2015A&A...574A..90A,doi:10.1051/0004-6361/201424579,S2CID 118504829, A90.
  9. ^"eta Psc".SIMBAD.Centre de données astronomiques de Strasbourg. Retrieved2017-07-30.
  10. ^ab"Naming Stars". IAU.org. Retrieved18 June 2018.
  11. ^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].
  12. ^Allen, Richard Hinckley (1963) [1899],Star Names: Their Lore and Meaning (rep. ed.),New York,NY:Dover Publications Inc., pp. 328–29,ISBN 0-486-21079-0{{citation}}:ISBN / Date incompatibility (help)
  13. ^"IAU Working Group on Star Names (WGSN)". Retrieved22 May 2016.
  14. ^"WG Triennial Report (2015-2018) - Star Names"(PDF). p. 5. Retrieved2018-07-14.
  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 theWayback Machine

External links

[edit]
Stars
Bayer
Flamsteed
Variable
HR
HD
Other
Exoplanets
Galaxies
Messier
NGC
Other
Retrieved from "https://en.wikipedia.org/w/index.php?title=Eta_Piscium&oldid=1319989795"
Categories:
Hidden categories:

[8]ページ先頭

©2009-2025 Movatter.jp