井宿三

**井宿三（雙子座γ）**
	Location of γ Geminorum (circled)
觀測資料; 曆元 J2000
星座	雙子座
星官	井（井宿）
赤經	06h 37m 42.71050s
赤緯	+16° 23′ 57.4095″
視星等（V）	1.915
特性
光谱分类	A1 IV
U−B 色指数	+0.137
B−V 色指数	+0.005
天体测定
徑向速度 (Rv)	-12.5 km/s
自行 (μ)	赤经：+13.81 mas/yr ; 赤纬：-54.96 mas/yr
视差 (π)	29.84 ± 2.23 mas
距离	109 ± 8 ly ; (34 ± 3 pc)
	軌道
繞行週期 (P)	4,614.51 days
偏心率 (e)	0.8933 ± 0.0013
近心点曆元 (T)	244399.13 ± 0.77
近心點幅角 (ω); (secondary)	312.60 ± 0.60°
半振幅 (K1); (primary)	11.881 ± 0.068 km/s
詳細資料
質量	2.81 M☉
半徑	3.3 R☉
表面重力 (log g)	3.60
亮度	123 L☉
溫度	9,260 K
金属量 [Fe/H]	–0.12 dex
自轉速度 (v sin i)	15 km/s
其他命名
	Alhena, 24 Geminorum, BD +16°1223, FK5 251, GCTP1539.00, HIP 31681, HD 47105, HR 2421, SAO 95912.

井宿三（雙子座γ）是雙子座第三亮的恆星，英文的固有名稱是Alhena和Almeisan。它的視星等為1.9等^[2]，即使在城市區域也很容易就能以裸眼看見。依據依巴谷衛星測量的視差，它與地球的距離大約是109光年（33秒差距）^[1]。

性質

井宿三是一顆已經耗盡核心供應的氫，演化進入次巨星階段的恆星。它的光譜與恆星分類的A0 IV相匹配^[3]。相較於太陽，質量是2.8倍^[6]，半徑是3.3倍^[7]，輻射的光度大約是太陽的123倍^[7]，從它外層的有效溫度大約是9,260K^[8]，使它的色調成為一顆典型的白色星^[11]。

這是一顆分光聯星，系統是有著高離心率的克卜勒軌道，週期12.6年（4,614.51天）^[5]。

語源

井宿三的英文名字Alhena出自阿拉伯的الهنعه Al Han'ah，意思為"頭部"（駱駝的頸部）；另一個備用的名字Almeisan 是阿拉伯語的المیسان Al Maisan，意思是閃耀的。Al Hanʽah的名稱與下列的恆星相關聯，包括井宿一（雙子座μ，Tejat Posterior）、井宿二（雙子座ν）、銊（雙子座η，Tejat Prior）和井宿四（雙子座ξ，Alzirr）。它們也與Al Nuḥātai相關聯，是有著雙峰的駱駝^[12]。

在Calendarium of Al Achsasi Al Mouakket這本恆星目錄中，這顆恆星的名稱是, Nir al Henat，是從拉丁文 Prima του al Henat翻過去的，意思是明亮的Al Henat^[13]。

在中文，井宿 (Jǐng Su)是中國的星官，類似於西方的星座，屬於這個星官的有雙子座γ、μ（井宿一）、ν（井宿二）、ξ（井宿四）、ε（井宿五）、36（井宿六）、ζ（井宿七）、λ（井宿八）^[14]。雙子座γ是井宿三(Jǐng Su sān，意思就是井宿的第三顆星^[15]。

在文化

Alhena是一艘荷蘭船隻的名稱，這艘船在1927年10月從義大利郵輪馬法爾達公主號救出了許多人^[16]。此外，美國的武裝貨船（英语：Amphibious cargo ship）USS Alhena (AKA-9)也以這顆恆星的名字命名。

参考资料

^ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 ^1.6 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 Gutierrez-Moreno, Adelina; et al, A System of photometric standards 1, Publicaciones Universidad de Chile, Department de Astronomy: 1–17, 1966, Bibcode:1966PDAUC...1....1G
^ ^3.0 ^3.1 Cowley, A.; et al, A study of the bright A stars. I. A catalogue of spectral classifications, Astronomical Journal, April 1969, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819
^ Evans, D. S., The Revision of the General Catalogue of Radial Velocities, Batten, Alan Henry; Heard, John Frederick (编), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, June 20–24, 1966, Bibcode:1967IAUS...30...57E
^ ^5.0 ^5.1 Lehmann, H.; et al, The spectroscopic binaries 21 Her and gamma Gem, Astronomy and Astrophysics, February 2002, 383: 558–567, Bibcode:2002A&A...383..558L, doi:10.1051/0004-6361:20011746
^ ^6.0 ^6.1 Shaya, Ed J.; Olling, Rob P., Very Wide Binaries and Other Comoving Stellar Companions: A Bayesian Analysis of the Hipparcos Catalogue, The Astrophysical Journal Supplement, January 2011, 192 (1): 2, Bibcode:2011ApJS..192....2S, arXiv:1007.0425 , doi:10.1088/0067-0049/192/1/2
^ ^7.0 ^7.1 ^7.2 ^7.3 Malagnini, M. L.; Morossi, C., Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars, Astronomy and Astrophysics Supplement Series, November 1990, 85 (3): 1015–1019, Bibcode:1990A&AS...85.1015M
^ ^8.0 ^8.1 ^8.2 ^8.3 Adelman, Saul J.; Philip, A. G. Davis, Elemental abundances of the B and A stars. 2: Gamma Geminorum, HD 60825, 7 Sextantis, HR 4817, and HR 5780, Astronomical Society of the Pacific, Publications, December 1994, 106 (706): 1239–1247, Bibcode:1994PASP..106.1239A, doi:10.1086/133501
^ Royer, F.; Zorec, J.; Gómez, A. E., Rotational velocities of A-type stars. III. Velocity distributions, Astronomy and Astrophysics, February 2007, 463 (2): 671–682, Bibcode:2007A&A...463..671R, arXiv:astro-ph/0610785 , doi:10.1051/0004-6361:20065224
^ ALHENA -- Spectroscopic binary, SIMBAD (Centre de Données astronomiques de Strasbourg), [2012-02-04], （原始内容存档于2014-12-29）
^ 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）
^ Allen, R. H. Star Names: Their Lore and Meaning Reprint. New York: Dover Publications Inc. 1963: 234 [2010-12-12]. ISBN 0-486-21079-0. （原始内容存档于2012-07-15）.
^ Knobel, E. B. Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket. Monthly Notices of the Royal Astronomical Society. June 1895, 55: 429. Bibcode:1895MNRAS..55..429K. doi:10.1093/mnras/55.8.429.
^ （中文） 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.
^ （中文）香港太空館 - 研究資源 - 亮星中英對照表（页面存档备份，存于互联网档案馆）, Hong Kong Space Museum. Accessed on line November 23, 2010.
^ http://www.markos.it/quaderni/plata.htm （页面存档备份，存于互联网档案馆） Italian account of the Principessa Malfeda.

[aaa474_2_653-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 ^1.6 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

[sps1966-2] 2.0 ^2.1 ^2.2 ^2.3 Gutierrez-Moreno, Adelina; et al, A System of photometric standards 1, Publicaciones Universidad de Chile, Department de Astronomy: 1–17, 1966, Bibcode:1966PDAUC...1....1G

[aj74_375-3] 3.0 ^3.1 Cowley, A.; et al, A study of the bright A stars. I. A catalogue of spectral classifications, Astronomical Journal, April 1969, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819

[rgcrv-4] Evans, D. S., The Revision of the General Catalogue of Radial Velocities, Batten, Alan Henry; Heard, John Frederick (编), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, June 20–24, 1966, Bibcode:1967IAUS...30...57E

[aaa383_558-5] 5.0 ^5.1 Lehmann, H.; et al, The spectroscopic binaries 21 Her and gamma Gem, Astronomy and Astrophysics, February 2002, 383: 558–567, Bibcode:2002A&A...383..558L, doi:10.1051/0004-6361:20011746

[apjss192_1_2-6] 6.0 ^6.1 Shaya, Ed J.; Olling, Rob P., Very Wide Binaries and Other Comoving Stellar Companions: A Bayesian Analysis of the Hipparcos Catalogue, The Astrophysical Journal Supplement, January 2011, 192 (1): 2, Bibcode:2011ApJS..192....2S, arXiv:1007.0425 , doi:10.1088/0067-0049/192/1/2

[aass85_3_1015-7] 7.0 ^7.1 ^7.2 ^7.3 Malagnini, M. L.; Morossi, C., Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars, Astronomy and Astrophysics Supplement Series, November 1990, 85 (3): 1015–1019, Bibcode:1990A&AS...85.1015M

[pasp106_706_1239-8] 8.0 ^8.1 ^8.2 ^8.3 Adelman, Saul J.; Philip, A. G. Davis, Elemental abundances of the B and A stars. 2: Gamma Geminorum, HD 60825, 7 Sextantis, HR 4817, and HR 5780, Astronomical Society of the Pacific, Publications, December 1994, 106 (706): 1239–1247, Bibcode:1994PASP..106.1239A, doi:10.1086/133501

[aaa463_2_671-9] Royer, F.; Zorec, J.; Gómez, A. E., Rotational velocities of A-type stars. III. Velocity distributions, Astronomy and Astrophysics, February 2007, 463 (2): 671–682, Bibcode:2007A&A...463..671R, arXiv:astro-ph/0610785 , doi:10.1051/0004-6361:20065224

[SIMBAD-10] ALHENA -- Spectroscopic binary, SIMBAD (Centre de Données astronomiques de Strasbourg), [2012-02-04], （原始内容存档于2014-12-29）

[csiro-11] 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）

[allen1963-12] Allen, R. H. Star Names: Their Lore and Meaning Reprint. New York: Dover Publications Inc. 1963: 234 [2010-12-12]. ISBN 0-486-21079-0. （原始内容存档于2012-07-15）.

[mnras55_429-13] Knobel, E. B. Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket. Monthly Notices of the Royal Astronomical Society. June 1895, 55: 429. Bibcode:1895MNRAS..55..429K. doi:10.1093/mnras/55.8.429.

[14] （中文） 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.

[15] （中文）香港太空館 - 研究資源 - 亮星中英對照表（页面存档备份，存于互联网档案馆）, Hong Kong Space Museum. Accessed on line November 23, 2010.

[16] ttp://www.markos.it/quaderni/plata.htm （页面存档备份，存于互联网档案馆） Italian account of the Principessa Malfeda.

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井宿三

性質

語源

在文化

参考资料

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