半人馬座ξ2

关于拜耳命名法的其它恆星系統，请见「半人馬座Xi1」。

半人馬座Xi² （ξ² Cen, ξ² Centauri）是在南天半人馬座的三星系統^[12]，這較寬的光學雙星視星等為裸眼可見的+4.30等^[2]，略比半人馬座ξ1A型主序星暗^[13]（+4.83等^[14]），年週視差6.98mas，距離太陽大約470光年。在這樣的距離，恆星會因為中間的星際塵埃造成消光，而使視星等減弱0.32等^[15]

已隱藏部分未翻譯内容，歡迎參與翻譯。

This system was discovered to be a single-lined spectroscopic binary in 1910 by American astronomer Joseph Haines Moore.^[16][17] The pair, component A, orbit each other with a period of 7.6497 days and an eccentricity of 0.35.^[8] The primary is a B-type star with a stellar classification of B1.5 V^[4] or B2 IV,^[5] depending on the source. This indicates it may be a main sequence star or a more evolved subgiant star. It has about 8.1^[4] times the mass of the Sun and radiates 1,702 times the solar luminosity from its outer atmosphere at an effective temperature of 20,790 K.^[9] It is a hybrid pulsator and shows spacings in both g and p modes.^[18]

A third star, component B, is a magnitude 9.38 F-type main sequence star with a classification of F7 V. It has 1.25^[9] times the mass of the Sun and radiates 2.4^[9] times the solar luminosity at an effective temperature of 6,194^[9] K. It lies at an angular separation of 25.1 arc seconds from the inner pair.^[3] They share a common proper motion, indicating they may be gravitationally bound with an orbital period of around 41,000 years.^[19]

The system has a peculiar velocity of 7004162000000000000♠16.2±4.2 km/s.^[6] It belongs to the Scorpius–Centaurus association and appears to be a member of the Gould's Belt.^[20]

半人馬座 ξ²

Centaurus constellation map.svg 半人馬座ξ2的位置
觀測資料 曆元 J2000.0
星座	半人馬座
星官
赤經	13h 06m 54.63940s[1]
赤緯	−49° 54′ 22.4823″[1]
視星等（V）	4.30[2] + 9.38[3]
特性
光谱分类	B1.5 V[4] or B2 IV[5] + F7 V[3]
U−B 色指数	−0.810[2]
B−V 色指数	−0.197[2]
天体测定
徑向速度 (Rv)	7001143000000000000♠+14.3±4.1[6] km/s
自行 (μ)	赤经：−26.15[1] mas/yr 赤纬：−12.03[1] mas/yr
视差 (π)	6.98 ± 0.24[1] mas
距离	470 ± 20 ly (143 ± 5 pc)
绝对星等 (MV)	−1.51[7]
軌道[8]
繞行週期 (P)	7.6497 d
偏心率 (e)	0.35
近心点 曆元 (T)	2418077.493 JD
近心點幅角 (ω) (secondary)	308.6°
半振幅 (K1) (primary)	38.8 km/s
詳細資料
ξ2 Cen A
質量	7000810000000000000♠8.1±0.1[4] M☉
表面重力 (log g)	7000411000000000000♠4.11±0.03[9]
亮度 (bolometric)	1,702[9] L☉
溫度	7004207900000000000♠20,790±335[9] K
自轉速度 (v sin i)	25[10] km/s
年齡	7001115000000000000♠11.5±3.7[4] Myr
ξ2 Cen B
質量	1.25[9] M☉
亮度	2.4[9] L☉
溫度	6,194[9] K
其他命名
半人馬座ξ2、CD−49° 7644、FK5 489、HD 113791、HIP 64004、HR 4942、SAO 223909[11]。
參考資料庫
SIMBAD	资料

參考

1. van Leeuwen, F., Validation of the new Hipparcos reduction, Astronomy and Astrophysics, 2007, 474 (2): 653–664, Bibcode:2007A&A...474..653V, S2CID 18759600, arXiv:0708.1752 , doi:10.1051/0004-6361:20078357.
2. Gutierrez-Moreno, Adelina; Moreno, Hugo, A photometric investigation of the Scorpio-Centaurus association, Astrophysical Journal Supplement, June 1968, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168.
3. Gahm, G. F.; et al, A study of visual double stars with early type primaries. I - Spectroscopic results, Astronomy and Astrophysics Supplement Series, January 1983, 51: 143–159, Bibcode:1983A&AS...51..143G.
4. Tetzlaff, N.; et al, A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun, Monthly Notices of the Royal Astronomical Society, January 2011, 410 (1): 190–200, Bibcode:2011MNRAS.410..190T, S2CID 118629873, arXiv:1007.4883 , doi:10.1111/j.1365-2966.2010.17434.x.
5. Hohle, M. M.; et al, Masses and luminosities of O- and B-type stars and red supergiants, Astronomische Nachrichten, April 2010, 331 (4): 349, Bibcode:2010AN....331..349H, S2CID 111387483, arXiv:1003.2335 , doi:10.1002/asna.200911355.
6. Bobylev, V. V.; Bajkova, A. T., Galactic kinematics from a sample of young massive stars, Astronomy Letters, August 2013, 39 (8): 532–549, Bibcode:2013AstL...39..532B, S2CID 118568203, arXiv:1307.1677 , doi:10.1134/S106377371308001X.
7. Anderson, E.; Francis, Ch., XHIP: An extended hipparcos compilation, Astronomy Letters, 2012, 38 (5): 331, Bibcode:2012AstL...38..331A, S2CID 119257644, arXiv:1108.4971 , doi:10.1134/S1063773712050015.
8. Pourbaix, D.; et al, S_B⁹: The ninth catalogue of spectroscopic binary orbits, Astronomy & Astrophysics, 2004, 424 (2): 727–732, Bibcode:2004A&A...424..727P, S2CID 119387088, arXiv:astro-ph/0406573 , doi:10.1051/0004-6361:20041213.
9. Gerbaldi, M.; et al, Binary systems with post-T Tauri secondaries, Astronomy and Astrophysics, November 2001, 379: 162–184, Bibcode:2001A&A...379..162G, doi:10.1051/0004-6361:20011298 .
10. Wolff, S. C.; et al, Rotational Velocities for B0-B3 Stars in Seven Young Clusters: Further Study of the Relationship between Rotation Speed and Density in Star-Forming Regions, The Astronomical Journal, 2007, 133 (3): 1092–1103, Bibcode:2007AJ....133.1092W, S2CID 119074863, arXiv:astro-ph/0702133 , doi:10.1086/511002.
11. ksi02 Cen -- Spectroscopic binary, SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), [2017-01-09], （原始内容存档于2022-10-31）.
12. Eggleton, P. P.; Tokovinin, A. A., A catalogue of multiplicity among bright stellar systems, Monthly Notices of the Royal Astronomical Society, September 2008, 389 (2): 869–879, Bibcode:2008MNRAS.389..869E, S2CID 14878976, arXiv:0806.2878 , doi:10.1111/j.1365-2966.2008.13596.x.
13. Backyard Astronomy, The Guides, Fog City Press: 248, 2003, ISBN 1877019321.
14. Gutierrez-Moreno, Adelina; Moreno, Hugo, A photometric investigation of the Scorpio-Centaurus association, Astrophysical Journal Supplement, June 1968, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168.
15. Gontcharov, G. A., Spatial distribution and kinematics of OB stars, Astronomy Letters, November 2012, 38 (11): 694–706, Bibcode:2012AstL...38..694G, S2CID 119108982, arXiv:1606.09028 , doi:10.1134/S1063773712110035.
16. Moore, Joseph Haines, Ten stars having variable radial velocities, Lick Observatory Bulletin, 1910, 6 (182): 55–59, Bibcode:1910LicOB...6...55M, doi:10.5479/ADS/bib/1910LicOB.6.55M.
17. Neubauer, F. J., The orbit of the spectroscopic binary ξ² Centauri, Lick Observatory Bulletin, 1931, 15: 107–108, Bibcode:1931LicOB..15..107N, doi:10.5479/ADS/bib/1931LicOB.15.107N .
18. Sharma, Awshesh N.; Bedding, Timothy R.; Saio, Hideyuki; White, Timothy R. Pulsating B stars in the Scorpius–Centaurus Association with TESS. Monthly Notices of the Royal Astronomical Society. 2022, 515: 828–840. Bibcode:2022MNRAS.515..828S. arXiv:2203.02582 . doi:10.1093/mnras/stac1816.
19. Tokovinin, A., Comparative statistics and origin of triple and quadruple stars, Monthly Notices of the Royal Astronomical Society, September 2008, 389 (2): 925–938, Bibcode:2008MNRAS.389..925T, S2CID 16452670, arXiv:0806.3263 , doi:10.1111/j.1365-2966.2008.13613.x.
20. Bobylev, V. V.; Bajkova, A. T., Kinematics of the Scorpius–Centaurus OB association, Astronomy Letters, September 2007, 33 (9): 571–583, Bibcode:2007AstL...33..571B, S2CID 15785349, arXiv:0708.0943 , doi:10.1134/S1063773707090010.

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