Beta2 Sagittarii

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For other stars with this Bayer designation, see β Sagittarii.
Beta2 Sagittarii
Diagram showing star positions and boundaries of the Sagittarius constellation and its surroundings
Location of β2 Sagittarii (circled)
Observation data
ICRS
)
Constellation Sagittarius
Right ascension 19h 23m 13.13745s[1]
Declination −44° 47′ 59.2051″[1]
Apparent magnitude (V) +4.29[2]
Characteristics
Spectral type F2/3 V[3] or F2 III[4]
U−B color index +0.07[2]
B−V color index +0.34[2]
Distance
134 ± 1 ly
(41.1 ± 0.3 pc)
Absolute magnitude (MV)+1.20[6]
Details
Myr
HR 7343, SAO 229654[10]
Database references
SIMBADdata

Beta2 Sagittarii (β2 Sagittarii, abbreviated Beta2 Sgr, β2 Sgr) is a

mas as seen from Earth,[1] it is located 134 light-years from the Sun
.

Based upon variations in its

astrometric binary system.[11] As such, its two components would be designated Beta2 Sagittarii A (officially named Arkab Posterior /ˈɑːrkæb pɒˈstɪəriər/, the traditional name of the system)[12][13]
and B.

Nomenclature

β2 Sagittarii (Latinised to Beta2 Sagittarii) is the system's Bayer designation. The designations of the two components as Beta2 Sagittarii 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).[14]

In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[15] to catalog and standardize proper names for stars. The WGSN approved the name Arkab Posterior for Beta2 Sagittarii on 5 October 2016 and it is now so included in the List of IAU-approved Star Names.[13] For such names relating to members of multiple star systems, and where a component letter (from e.g. Washington Double Star Catalog) is not explicitly listed, the WGSN says that the name should be understood to be attributed to the brightest component by visual brightness.[16]

In

Chinese name for Beta2 Sagittarii itself is 天淵一 (Tiān Yuān yī, English: the First Star of Celestial Spring.)[17]

Properties

Houk (1978) categorizes the visible component (Beta2 Sagittarii A) as an

oblate shape with an equatorial bulge that is 22% larger than the polar radius.[9] Beta2 Sagittarii has an estimated 1.4[7] times the mass of the Sun and is around 933[7]
 million years old.

References

  1. ^
    S2CID 18759600
    .
  2. ^
    Bibcode:1966CoLPL...4...99J
    .
  3. ^
    Bibcode:1978mcts.book.....H
    .
  4. ^
    doi:10.1086/111786
    .
  5. ^
    S2CID 56118016
    .
  6. S2CID 119257644
    .
  7. ^
    S2CID 33401607
    .
  8. S2CID 118665352
    .
  9. ^
    S2CID 119273474
    .
  10. ^ "bet02 Sgr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-10.
  11. S2CID 14878976
    .
  12. ISBN 978-1-931559-44-7
    .
  13. ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
  14. arXiv:1012.0707 [astro-ph.SR
    ].
  15. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  16. ^ "Bulletin of the IAU Working Group on Star Names, No. 2" (PDF). Retrieved 16 December 2017.
  17. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 2 日
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