库楼三

**库楼三（半人马座θ）**
	Location of θ Centauri (circled)
观测资料; 历元 J2000.0
星座	半人马座
星官	库楼（角宿）
赤经	14h 06m 40.94752s
赤纬	–36° 22′ 11.8371″
视星等（V）	+2.06
特性
光谱分类	K0 III
U−B 色指数	+0.90
B−V 色指数	+0.99
天体测定
径向速度 (Rv)	+1.3 km/s
自行 (μ)	赤经：–520.53 mas/yr ; 赤纬：–518.06 mas/yr
视差 (π)	55.45 ± 0.20 mas
距离	58.8 ± 0.2 ly ; (18.03 ± 0.07 pc)
绝对星等 (MV)	0.87
详细资料
半径	10.6 R☉
表面重力 (log g)	2.75
亮度	60 L☉
温度	4,980 K
金属量 [Fe/H]	0.03 dex
其他命名
	Menkent, Haratan, Gl 539, HR 5288, CD−35°9260, CP−35°6109, HD 123139, LHS 2858, GCTP 3206.00, SAO 205188, FK5 520, HIP 68933, GC 19033, CCDM J14067-3622
参考数据库
SIMBAD	资料

库楼三（半人马θ，θ Cen）的英文名字是Menkent^[10]，是位于南半球半人马座的一颗恒星，它的视星等是2.06等^[2]，是半人马座的第四亮星。它与太阳的距离很近，使用视差的技术测量出只有58.8光年（18.0秒差距）^[1]。

它已经演化成巨星，恒星光谱是K0 III^[3]。以干涉测量术测得的角直径，经过周边昏暗修正后是5.46 ± 0.06 毫角秒^[11]，依据测量得到的距离估计，它实际的半径是太阳半径的10.6倍^[6]。恒星表面的有效温度是4,980K ^[7]，呈现低温的橙色，是一颗K型星^[12]。在这颗恒星也检测到软X射线，估计它的X射线亮度是1.4 × 10²⁷ erg s⁻¹^[13]。

名称

半人马θ 是拜耳命名法给予的名称（拉丁文的写法是Theta Centauri）。

它的固有名称是Menkent，可能是源自阿拉伯文的ألمنكب ألقنتوس（al mankib al-qanturis），意思是"半人马的肩膀"。在2016年，国际天文学联合会的IAU恒星名称工作组（WGSN）^[14]建立目录规范了一些恒星的专属名字，在2016年8月21日批准这颗恒星的正式名称为Menkent，并登录在IAU的恒星目录^[10]。

在中国，这颗星称为库楼三，属于星官库楼（Kù Lóu），意思是军械库；为角宿下的一个星官。同属于这个星官的还有半人马座ζ、半人马座η、半人马座2、HD 117440、半人马座f、半人马座γ、半人马座τ、半人马座D、和半人马座σ^[15]。因此，库楼三是库楼的第三颗星^[16]。

参考资料

^ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 van Leeuwen, F. Validation of the new Hipparcos reduction. Astronomy and Astrophysics. November 2007, 474 (2): 653–664. Bibcode:2007A&A...474..653V. arXiv:0708.1752  . doi:10.1051/0004-6361:20078357.
^ ^2.0 ^2.1 ^2.2 ^2.3 Johnson, H. L.; et al. UBVRIJKL photometry of the bright stars. Communications of the Lunar and Planetary Laboratory. 1966, 4 (99): 99. Bibcode:1966CoLPL...4...99J.
^ ^3.0 ^3.1 Gray, R. O.; et al, Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I, The Astronomical Journal, July 2006, 132 (1): 161–170, Bibcode:2006AJ....132..161G, arXiv:astro-ph/0603770  , doi:10.1086/504637
^ Wielen, R.; et al, Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions, Veröff. Astron. Rechen-Inst. Heidelb (Astronomisches Rechen-Institut Heidelberg), 1999, 35 (35), Bibcode:1999VeARI..35....1W
^ Elgarøy, Øystein; Engvold, Oddbjørn; Lund, Niels, The Wilson-Bappu effect of the MgII K line - dependence on stellar temperature, activity and metallicity, Astronomy and Astrophysics, March 1999, 343: 222–228, Bibcode:1999A&A...343..222E
^ ^6.0 ^6.1 Lang, Kenneth R., Astrophysical formulae, Astronomy and astrophysics library 1 3rd, Birkhäuser, 2006 [2017-06-04], ISBN 3-540-29692-1, （原始内容存档于2019-05-20） . The radius (R_*) is given by:
${\begin{aligned}2\cdot R_{*}&={\frac {(18.03\cdot 5.46\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 21.2\cdot R_{\bigodot }\end{aligned}}$
^ ^7.0 ^7.1 ^7.2 ^7.3 Jones, K. L.; et al, Spectroscopic investigation of cool giants and the authenticity of their reported microwave emission, Monthly Notices of the Royal Astronomical Society, June 1992, 256 (3): 535–544, Bibcode:1992MNRAS.256..535J, doi:10.1093/mnras/256.3.535
^ Kaler, James B., MENKENT (Theta Centauri), Stars (University of Illinois), [2012-03-01], （原始内容存档于2021-05-13）
^ LHS 2858 -- High proper-motion Star, SIMBAD Astronomical Object Database (Centre de Données astronomiques de Strasbourg), [2012-03-01], （原始内容存档于2019-05-21）
^ ^10.0 ^10.1 IAU Catalog of Star Names. [28 July 2016]. （原始内容存档于2018-07-07）.
^ Richichi, A.; Percheron, I.; Khristoforova, M., CHARM2: An updated Catalog of High Angular Resolution Measurements, Astronomy and Astrophysics, February 2005, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039
^ The Colour of Stars, Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004 [2012-01-16], （原始内容存档于2012-03-10）
^ Schroeder, K.-P.; Huensch, M.; Schmitt, J. H. M. M., X-ray activity and evolutionary status of late-type giants, Astronomy and Astrophysics, July 1998, 335: 591–595, Bibcode:1998A&A...335..591S
^ IAU Working Group on Star Names (WGSN). [22 May 2016]. （原始内容存档于2019-03-30）.
^ （中文） 中国星座神话, written by 陈久金. Published by 台湾书房出版有限公司, 2005, ISBN 978-986-7332-25-7.
^ （中文）香港太空馆 - 研究资源 - 亮星中英对照表互联网档案馆的存档，存档日期2011-01-30., Hong Kong Space Museum. Accessed on line November 23, 2010.

[aaa474_2_653-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 van Leeuwen, F. Validation of the new Hipparcos reduction. Astronomy and Astrophysics. November 2007, 474 (2): 653–664. Bibcode:2007A&A...474..653V. arXiv:0708.1752  . doi:10.1051/0004-6361:20078357.

[clpl4_99-2] 2.0 ^2.1 ^2.2 ^2.3 Johnson, H. L.; et al. UBVRIJKL photometry of the bright stars. Communications of the Lunar and Planetary Laboratory. 1966, 4 (99): 99. Bibcode:1966CoLPL...4...99J.

[aj132_1_161-3] 3.0 ^3.1 Gray, R. O.; et al, Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I, The Astronomical Journal, July 2006, 132 (1): 161–170, Bibcode:2006AJ....132..161G, arXiv:astro-ph/0603770  , doi:10.1086/504637

[scfs-4] Wielen, R.; et al, Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions, Veröff. Astron. Rechen-Inst. Heidelb (Astronomisches Rechen-Institut Heidelberg), 1999, 35 (35), Bibcode:1999VeARI..35....1W

[aaa343_222-5] Elgarøy, Øystein; Engvold, Oddbjørn; Lund, Niels, The Wilson-Bappu effect of the MgII K line - dependence on stellar temperature, activity and metallicity, Astronomy and Astrophysics, March 1999, 343: 222–228, Bibcode:1999A&A...343..222E

[lang2006-6] 6.0 ^6.1 Lang, Kenneth R., Astrophysical formulae, Astronomy and astrophysics library 1 3rd, Birkhäuser, 2006 [2017-06-04], ISBN 3-540-29692-1, （原始内容存档于2019-05-20） . The radius (R_*) is given by:
${\begin{aligned}2\cdot R_{*}&={\frac {(18.03\cdot 5.46\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 21.2\cdot R_{\bigodot }\end{aligned}}$

[mnras256_3_535-7] 7.0 ^7.1 ^7.2 ^7.3 Jones, K. L.; et al, Spectroscopic investigation of cool giants and the authenticity of their reported microwave emission, Monthly Notices of the Royal Astronomical Society, June 1992, 256 (3): 535–544, Bibcode:1992MNRAS.256..535J, doi:10.1093/mnras/256.3.535

[kaler-8] Kaler, James B., MENKENT (Theta Centauri), Stars (University of Illinois), [2012-03-01], （原始内容存档于2021-05-13）

[SIMBAD-9] LHS 2858 -- High proper-motion Star, SIMBAD Astronomical Object Database (Centre de Données astronomiques de Strasbourg), [2012-03-01], （原始内容存档于2019-05-21）

[IAU-CSN-10] 10.0 ^10.1 IAU Catalog of Star Names. [28 July 2016]. （原始内容存档于2018-07-07）.

[aaa431_773-11] Richichi, A.; Percheron, I.; Khristoforova, M., CHARM2: An updated Catalog of High Angular Resolution Measurements, Astronomy and Astrophysics, February 2005, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039

[csiro-12] The Colour of Stars, Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004 [2012-01-16], （原始内容存档于2012-03-10）

[aaa335_591-13] Schroeder, K.-P.; Huensch, M.; Schmitt, J. H. M. M., X-ray activity and evolutionary status of late-type giants, Astronomy and Astrophysics, July 1998, 335: 591–595, Bibcode:1998A&A...335..591S

[WGSN-14] IAU Working Group on Star Names (WGSN). [22 May 2016]. （原始内容存档于2019-03-30）.

[15] （中文） 中国星座神话, written by 陈久金. Published by 台湾书房出版有限公司, 2005, ISBN 978-986-7332-25-7.

[16] （中文）香港太空馆 - 研究资源 - 亮星中英对照表互联网档案馆的存档，存档日期2011-01-30., Hong Kong Space Museum. Accessed on line November 23, 2010.

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观测资料历元 J2000.0
Location of θ Centauri (circled)
星座	半人马座
星官	库楼（角宿）
赤经	14^h 06^m 40.94752^s^[1]
赤纬	–36° 22′ 11.8371″^[1]
视星等（V）	+2.06^[2]
特性
光谱分类	K0 III^[3]
U−B 色指数	+0.90^[2]
B−V 色指数	+0.99^[2]
天体测定

径向速度 (R_v)	+1.3^[4] km/s
自行 (μ)	赤经：–520.53^[1] mas/yr 赤纬：–518.06^[1] mas/yr
视差 (π)	55.45 ± 0.20^[1] mas
距离	58.8 ± 0.2 ly (18.03 ± 0.07 pc)
绝对星等 (M_V)	0.87^[5]

详细资料

半径	10.6^[6] R_☉
表面重力 (log g)	2.75^[7]
亮度	60^[8] L_☉
温度	4,980^[7] K
金属量 [Fe/H]	0.03^[7] dex

其他命名
Menkent, Haratan, Gl 539, HR 5288, CD−35°9260, CP−35°6109, HD 123139, LHS 2858, GCTP 3206.00, SAO 205188, FK5 520, HIP 68933, GC 19033, CCDM J14067-3622^[9]
参考数据库
SIMBAD	资料