Zeta Arae

ζ Arae
Location of ζ Arae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ara
Right ascension 16h 58m 37.21217s[1]
Declination –55° 59′ 24.5203″[1]
Apparent magnitude (V) 3.13[2]
Characteristics
Spectral type K3 III[3]
U−B color index +1.96[2]
B−V color index +1.60[2]
Astrometry
Radial velocity (Rv)–6.0[4] km/s
Proper motion (μ) RA: –17.80[1] mas/yr
Dec.: –36.67[1] mas/yr
Parallax (π)5.7725 ± 0.1727 mas[5]
Distance570 ± 20 ly
(173 ± 5 pc)
Absolute magnitude (MV)–3.95[6]
Details
Mass7-8[7] M☉
Radius114[7] R☉
Luminosity3,800[7] L☉
Surface gravity (log g)1.20[7] cgs
Temperature4,246[7] K
Metallicity [Fe/H]–0.40[8] dex
Age40~50 Myr
Other designations
Tseen Yin, GJ 9581, SAO 244315, HD 152786, FK5 631, HIP 83081, HR 6285, CPD−55° 7766[9]
Database references
SIMBADdata
ARICNSdata

Zeta Arae (ζ Ara, ζ Arae) is the third-brightest star in the southern constellation Ara.[10] The apparent visual magnitude of this star is 3.1,[2] which can be seen from suburban skies in the southern hemisphere. From the parallax measurements, it is located at a distance of 490 light-years (150 parsecs) from Earth.[1]

The spectrum of this star matches a stellar classification of K3 III.[3] The luminosity class of 'III' indicates this is a giant star that has exhausted the hydrogen at its core and evolved away from the main sequence. It is radiating energy from its outer atmosphere at an effective temperature of 4,246 K which is what gives it the orange hue of a K-type star.[11] This star displays an excess of infrared emission that may indicate circumstellar matter.[12]

In Chinese, 龜 (Guī), meaning Tortoise, refers to an asterism consisting of ζ Arae, ε1 Arae, γ Arae, δ Arae and η Arae.[13] Consequently, the Chinese name for ζ Arae itself is 龜五 (Guī wǔ, English: the Fifth Star of Tortoise.)[14]

Allen called it Tseen Yin /ˌsiːnˈjɪn/, together with δ Arae, from the Chinese 天陰 (Mandarin pronunciation tiānyīn) "dark sky".[15] However, 天陰 is in Aries.[16][17] so Allen probably confused constellation "Ara" with "Ari".

  1. ^ a b c d e Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference clpl4_99 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1978 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference scfs was invoked but never defined (see the help page).
  5. ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  6. ^ Cite error: The named reference aaa342_831 was invoked but never defined (see the help page).
  7. ^ a b c d e Cite error: The named reference cruzalebes was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference mnras256_3_535 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Kaler, Jim (13 July 2012). "Zeta Arae". Stars. University of Illinois. Retrieved 12 September 2019.
  11. ^ Cite error: The named reference csiro was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference aaa323_513 was invoked but never defined (see the help page).
  13. ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  14. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 1 日
  15. ^ Cite error: The named reference allen was invoked but never defined (see the help page).
  16. ^ Chevalier, S., and Tsuchihashi, P., (1911): "Catalogue d'Étoiles fixes, observés a Pekin sous l'Empereur Kien Long (Qianlong (Chien-Lung)), XVIIIe siecle", Annales de l'Observatoire Astronomique de Zô-Sé.
  17. ^ 伊世同 (Yi Shi Tong) (1981): 『中西対照恒星図表』科学出版社.(in Chinese)