开阳增一

开阳增一或辅（英语：Alcor /ˈælkɔːr/^[9]）是大熊座的一个双星系统。它是开阳的较暗淡的伴星，两星共同构成裸眼可辨别的目视双星，位于北斗七星的柄上。根据依巴谷卫星测量，两者都位于距离太阳约83光年处。

开阳增一、辅

开阳和开阳增一在北斗七星中的位置
观测资料 历元 J2000.0
星座	大熊座
星官	辅
赤经	13h 25m 13.53783s[1]
赤纬	+54° 59′ 16.6548″[1]
视星等（V）	+3.99[2]
特性
光谱分类	A5Vn[3] / M3-4[4]
天体测定
径向速度 (Rv)	−9.6[5] km/s
视差 (π)	39.91 ± 0.13[1] mas
距离	81.7 ± 0.3 ly (25.06 ± 0.08 pc)
绝对星等 (MV)	+2.00[2]
详细资料
Alcor A
质量	1.84[6] M☉
半径	1.846[7] R☉
表面重力 (log g)	4.25[8]
亮度	14.03[6] L☉
温度	8,221[8] K
自转速度 (v sin i)	228[6] km/s
Alcor B
质量	0.25[4] M☉
年龄	0.5 ± 0.1[2] Gyr
其他命名
g Ursae Majoris, 80 Ursae Majoris, BD+55 1603, CCDM J13240+5456D, GC 18155, HD 116842, HIP 65477, HR 5062, PPM 34021, SAO 28751, WDS J13239+5456C
参考数据库
SIMBAD	资料

命名法

根据佛兰斯蒂德命名法，开阳增一的名称为大熊座80（Ursae Majoris 80）。Alcor来自阿拉伯语سها‎ Suhā/Sohā，意为是“被遗忘者”或“被忽略者”，作为开阳的伴星而闻名。^[10]

2009年，发现开阳增一的联星Alcor B，是8.8星等的红矮星。

2016年，国际天文联会组织了IAU恒星名称工作组（WGSN）^[11]，对恒星的专名进行分类和标准化。WGSN于2016年7月发布的第一份公告包含了WGSN批准的首两批名称的表格^[12]；其中包括大熊座80的西方名Alcor。^[13]

参见

• 开阳双星
• 开阳 (恒星)
• 辅 (星官)

参考文献

1. 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. Mamajek, Eric E.; Kenworthy, Matthew A.; Hinz, Philip M.; Meyer, Michael R. Discovery of a Faint Companion to Alcor Using MMT/AO 5 μm Imaging. The Astronomical Journal. 2010, 139 (3): 919–925. Bibcode:2010AJ....139..919M. arXiv:0911.5028 . doi:10.1088/0004-6256/139/3/919.
3. Gray, R. O; Garrison, R. F. The late A-type stars - Refined MK classification, confrontation with Stromgren photometry, and the effects of rotation. Astrophysical Journal Supplement Series. 1989, 70: 623. Bibcode:1989ApJS...70..623G. doi:10.1086/191349.
4. Zimmerman, Neil; Oppenheimer, Ben R; Hinkley, Sasha; Brenner, Douglas; Parry, Ian R; Sivaramakrishnan, Anand; Hillenbrand, Lynne; Beichman, Charles; Crepp, Justin R; Vasisht, Gautam; Roberts, Lewis C; Burruss, Rick; King, David L; Soummer, Rémi; Dekany, Richard; Shao, Michael; Bouchez, Antonin; Roberts, Jennifer E; Hunt, Stephanie. Parallactic Motion for Companion Discovery: An M-Dwarf Orbiting Alcor. The Astrophysical Journal. 2010, 709 (2): 733–740. Bibcode:2010ApJ...709..733Z. arXiv:0912.1597 . doi:10.1088/0004-637X/709/2/733.
5. Kidger, Mark R; Martín-Luis, Fabiola. High-Precision Near-Infrared Photometry of a Large Sample of Bright Stars Visible from the Northern Hemisphere. The Astronomical Journal. 2003, 125 (6): 3311. Bibcode:2003AJ....125.3311K. doi:10.1086/374996.
6. Zorec, J; Royer, F. Rotational velocities of A-type stars. IV. Evolution of rotational velocities. Astronomy & Astrophysics. 2012, 537: A120. Bibcode:2012A&A...537A.120Z. arXiv:1201.2052 . doi:10.1051/0004-6361/201117691.
7. Jones, Jeremy; White, R. J; Boyajian, T; Schaefer, G; Baines, E; Ireland, M; Patience, J; Ten Brummelaar, T; McAlister, H; Ridgway, S. T; Sturmann, J; Sturmann, L; Turner, N; Farrington, C; Goldfinger, P. J. The Ages of A-Stars. I. Interferometric Observations and Age Estimates for Stars in the Ursa Major Moving Group. The Astrophysical Journal. 2015, 813 (1): 58. Bibcode:2015ApJ...813...58J. arXiv:1508.05643 . doi:10.1088/0004-637X/813/1/58.
8. David, Trevor J; Hillenbrand, Lynne A. The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets. The Astrophysical Journal. 2015, 804 (2): 146. Bibcode:2015ApJ...804..146D. arXiv:1501.03154 . doi:10.1088/0004-637X/804/2/146.
9. Kunitzsch, Paul; Smart, Tim. A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations 2nd rev. Cambridge, Massachusetts: Sky Pub. 2006. ISBN 978-1-931559-44-7.
10. Bohigian, George M. An Ancient Eye Test—Using the Stars. Survey of Ophthalmology. 2008, 53 (5): 536–9. PMID 18929764. doi:10.1016/j.survophthal.2008.06.009.
11. IAU Working Group on Star Names (WGSN). [22 May 2016]. （原始内容存档于2020-05-13）.
12. Bulletin of the IAU Working Group on Star Names, No. 1 (PDF). [28 July 2016]. （原始内容存档 (PDF)于2018-04-17）.
13. IAU Catalog of Star Names. [28 July 2016]. （原始内容存档于2018-07-07）.

外部链接

• Alcor （页面存档备份，存于互联网档案馆） at Jim Kaler's Stars website
• WikiSky上关于开阳增一的内容：DSS2, SDSS, GALEX, IRAS, 氢α, X射线, 天文照片, 天图, 文章和图片