梅西耶23

M 23
M 23
	在人马座的疏散星团M23。
观测资料 (J2000 历元)
星座	人马座
赤经	17h 57m 04s
赤纬	−18° 59′ 06″
距离	2,050 ly（628 pc）
视星等 (V)	5.5
视大小 (V)	35′
物理特征
质量	1,206 M☉
半径	8 ly
估计年龄	330±100 myr
其他特征	M23、NGC 6494、 Cr 356、C 1753-190
	相关条目：疏散星团、NGC天体表

M23，也称为NGC 6494，是靠近人马座这个星座西北方的一个疏散星团 ^[7]。它是查尔斯·梅西耶于1764年6月20日发现的^[3]。在良好的观测环境下，可以用双筒望远镜或中等大小的望远镜看见它^[3]。它位于大范围的气体含尘埃云的前面，但与它们似乎没有关连^[4]。它在太阳运行平面的5度之内，因此有时会被月球遮蔽到^[8]。

这个星团的中心距离地球约2,050光年，估计成员的数量在169^[9]到414，直接计数的质量为7033239819129999999♠1,206 M_☉；使用维里定理推算的质量则为7033264874859999999♠1,332 M_☉ ^[4]。推测星团的年龄在3.3亿年，与太阳比较的金属量 [Fe/H] = −0.04^[5]。最亮的恒星视星等为+9.3^[10]，成员中有5颗是红巨星的候选者^[11]，远在南方的人马座VV是橙色的变星^[a]，是渐近巨星支的候选者^[12]。

有一颗6等星显示在图的右上角，也就是在西北方的远处，这是一颗前景星：HD 163245（HR 6679）。它的视差偏移是6992479538908259065♠9.8912±0.0518 mas，考虑到自行，这意味着它的距离大约在101秒差距（330光年）之外^[13]。

图集

显示M23位置的星图。

注解和参考资料

注解

^ 在蓝白色的7等星HD 163427东侧

参考资料

^ Wu, Zhen-Yu; et al, The orbits of open clusters in the Galaxy, Monthly Notices of the Royal Astronomical Society, November 2009, 399 (4): 2146–2164, Bibcode:2009MNRAS.399.2146W, arXiv:0909.3737 , doi:10.1111/j.1365-2966.2009.15416.x.
^ ^2.0 ^2.1 Kharchenko, N. V.; et al, Astrophysical parameters of Galactic open clusters, Astronomy and Astrophysics, 2005, 438 (3): 1163–1173, Bibcode:2005A&A...438.1163K, arXiv:astro-ph/0501674 , doi:10.1051/0004-6361:20042523.
^ ^3.0 ^3.1 ^3.2 Thompson, Robert; Thompson, Barbara, Illustrated Guide to Astronomical Wonders: From Novice to Master Observer, DIY science, O'Reilly Media, Inc.: 408, 2007 [2021-08-20], ISBN 978-0596526856, （原始内容存档于2023-07-28）
^ ^4.0 ^4.1 ^4.2 McNamara, B. J.; Sanders, W. L., A virial mass determination of the open cluster NGC 6494, Astronomy and Astrophysics, February 1983, 118 (2): 361–362, Bibcode:1983A&A...118..361M.
^ ^5.0 ^5.1 Netopil, M.; Paunzen, E.; Heiter, U.; Soubiran, C., On the metallicity of open clusters. III. Homogenised sample, Astronomy & Astrophysics, 2016, 585: A150, Bibcode:2016A&A...585A.150N, arXiv:1511.08884 , doi:10.1051/0004-6361/201526370.
^ M 23. SIMBAD. 斯特拉斯堡天文资料中心.
^ Gilmour, Jess K., The Practical Astronomer's Deep-sky Companion, The Patrick Moore Practical Astronomy Series, Springer Science & Business Media: 121, 2003, ISBN 978-1852334741.
^ Ridgway, S. T.; et al, Twenty-eight angular diameters for late-type stars by the lunar occultation technique, Astronomical Journal, February 1979, 84: 247–256, Bibcode:1979AJ.....84..247R, doi:10.1086/112414. See VV Sgr.
^ Sanders, W. L.; Schroeder, R., Membership in the open cluster NGC 6494, Astronomy and Astrophysics, August 1980, 88: 102–107, Bibcode:1980A&A....88..102S.
^ Sanders, W. L., UBV photometry of NGC 6494 and metallicity considerations, Astronomy and Astrophysics Supplement Series, September 1990, 84 (3): 615–618, Bibcode:1990A&AS...84..615S.
^ Claria, J. J.; Lapasset, E., Multicolour photometry of red giants in three southern open clusters, Monthly Notices of the Royal Astronomical Society, November 15, 1989, 241 (2): 301–310, Bibcode:1989MNRAS.241..301C, doi:10.1093/mnras/241.2.301 
^ Jura, M., Mass-losing red giants in open clusters, Astrophysical Journal, Part 1, February 1987, 313: 743–749, Bibcode:1987ApJ...313..743J, doi:10.1086/165012.
^ Brown, A. G. A.; Vallenari, A.; Prusti, T.; de Bruijne, J. H. J.; et al. Gaia Data Release 2. Summary of the contents and survey properties. Astronomy & Astrophysics. 2018. Bibcode:2018A&A...616A...1G. arXiv:1804.09365 . doi:10.1051/0004-6361/201833051. VizieR中此天体在盖亚望远镜第二批数据发布的记录

外部链接

Messier 23, SEDS Messier pages （页面存档备份，存于互联网档案馆）
WikiSky上关于梅西耶23的内容：DSS2, SDSS, GALEX, IRAS, 氢α, X射线, 天文照片, 天图, 文章和图片

[12] 在蓝白色的7等星HD 163427东侧

[Wu2009-1] Wu, Zhen-Yu; et al, The orbits of open clusters in the Galaxy, Monthly Notices of the Royal Astronomical Society, November 2009, 399 (4): 2146–2164, Bibcode:2009MNRAS.399.2146W, arXiv:0909.3737 , doi:10.1111/j.1365-2966.2009.15416.x.

[kharchenko2005-2] 2.0 ^2.1 Kharchenko, N. V.; et al, Astrophysical parameters of Galactic open clusters, Astronomy and Astrophysics, 2005, 438 (3): 1163–1173, Bibcode:2005A&A...438.1163K, arXiv:astro-ph/0501674 , doi:10.1051/0004-6361:20042523.

[Thompson2007-3] 3.0 ^3.1 ^3.2 Thompson, Robert; Thompson, Barbara, Illustrated Guide to Astronomical Wonders: From Novice to Master Observer, DIY science, O'Reilly Media, Inc.: 408, 2007 [2021-08-20], ISBN 978-0596526856, （原始内容存档于2023-07-28）

[McNamara1983-4] 4.0 ^4.1 ^4.2 McNamara, B. J.; Sanders, W. L., A virial mass determination of the open cluster NGC 6494, Astronomy and Astrophysics, February 1983, 118 (2): 361–362, Bibcode:1983A&A...118..361M.

[netopil2016-5] 5.0 ^5.1 Netopil, M.; Paunzen, E.; Heiter, U.; Soubiran, C., On the metallicity of open clusters. III. Homogenised sample, Astronomy & Astrophysics, 2016, 585: A150, Bibcode:2016A&A...585A.150N, arXiv:1511.08884 , doi:10.1051/0004-6361/201526370.

[SIMBAD-6] M 23. SIMBAD. 斯特拉斯堡天文资料中心.

[Gilmour2003-7] Gilmour, Jess K., The Practical Astronomer's Deep-sky Companion, The Patrick Moore Practical Astronomy Series, Springer Science & Business Media: 121, 2003, ISBN 978-1852334741.

[Ridgway1979-8] Ridgway, S. T.; et al, Twenty-eight angular diameters for late-type stars by the lunar occultation technique, Astronomical Journal, February 1979, 84: 247–256, Bibcode:1979AJ.....84..247R, doi:10.1086/112414. See VV Sgr.

[Sanders1980-9] Sanders, W. L.; Schroeder, R., Membership in the open cluster NGC 6494, Astronomy and Astrophysics, August 1980, 88: 102–107, Bibcode:1980A&A....88..102S.

[Sanders1990-10] Sanders, W. L., UBV photometry of NGC 6494 and metallicity considerations, Astronomy and Astrophysics Supplement Series, September 1990, 84 (3): 615–618, Bibcode:1990A&AS...84..615S.

[Claria1989-11] Claria, J. J.; Lapasset, E., Multicolour photometry of red giants in three southern open clusters, Monthly Notices of the Royal Astronomical Society, November 15, 1989, 241 (2): 301–310, Bibcode:1989MNRAS.241..301C, doi:10.1093/mnras/241.2.301 

[Jura1987-13] Jura, M., Mass-losing red giants in open clusters, Astrophysical Journal, Part 1, February 1987, 313: 743–749, Bibcode:1987ApJ...313..743J, doi:10.1086/165012.

[14] Brown, A. G. A.; Vallenari, A.; Prusti, T.; de Bruijne, J. H. J.; et al. Gaia Data Release 2. Summary of the contents and survey properties. Astronomy & Astrophysics. 2018. Bibcode:2018A&A...616A...1G. arXiv:1804.09365 . doi:10.1051/0004-6361/201833051. VizieR中此天体在盖亚望远镜第二批数据发布的记录

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图集

相关条目

注解和参考资料

注解

参考资料

外部链接