M50 (疏散星團)

M 50
M 50
	當天狼星在南方天空時，梅西耶50位於天狼星北方8°和東方3°的角上（觀察時的左側）。
觀測資料 (J2000 曆元)
星座	麒麟座
赤經	07h 02m 47.5s
赤緯	−08° 20′ 16″
距離	2,870 ly（881 pc）
視星等 (V)	5.9
視大小 (V)	16.0′
物理特徵
質量	> 285 M☉ M☉
半徑	8.9 ly（2.73 pc）
估計年齡	140 Myr
其他特徵	M50, NGC 2323, Cr 124, C 0700-082, OCl 559
	相關條目：疏散星团、NGC天體表

M50或梅西耶50，也稱為NGC 2323，是位於麒麟座的一個疏散星團。它可能在1711年之前就被卡西尼發現，梅西耶在1772年4月5日觀測比拉彗星時，又再度獨立發現它。它有時也被描述或心形或鈍箭頭^[3]。

M50距離地球大約2,900光年^[2]，雖然與大犬座 OB1星協接近，但估計關係並不緊密^[4]。它的核心半徑為5.9 ly（1.8 pc）^[6]，範圍為17.8 ly（5.46 pc）^[4]。這個星團有508個已確認成員和109個可能的成員；它們的總質量超過7032566736750000000♠285 M_☉，平均恆星密度是每立方秒差距1.3顆恆星^[4]。星團的歷史大約有1.4億年^[1]，有兩顆大質量的白矮星^[7]和兩顆特殊恆星^[8]。

圖集

梅西耶50
天狼星和M41（右下角）、M50（左上）和NGC 2360 （左下）。

參考資料和註解

^ ^1.0 ^1.1 ^1.2 ^1.3 Frolov, V. N.; et al, Investigation of the open star cluster NGC 2323 (M50) based on the proper motions and photometry of its constituent stars, Astronomy Letters, February 2012, 38 (2): 74–86, Bibcode:2012AstL...38...74F, doi:10.1134/S106377371202003X.
^ ^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.: 321, 2007, ISBN 978-0596526856
^ ^4.0 ^4.1 ^4.2 ^4.3 ^4.4 Claria, J. J.; et al, Photometric study of the open cluster NGC 2323, Astronomy and Astrophysics Supplement, February 1998, 128: 131–138, Bibcode:1998A&AS..128..131C, doi:10.1051/aas:1998130 
^ M 50. SIMBAD. 斯特拉斯堡天文資料中心.
^ Sharma, Saurabh; et al, Mass Functions and Photometric Binaries in Nine Open Clusters, The Astronomical Journal, May 2008, 135 (5): 1934–1945, Bibcode:2008AJ....135.1934S, arXiv:0803.0122  , doi:10.1088/0004-6256/135/5/1934.
^ Cummings, Jeffrey D.; et al, Two Massive White Dwarfs from NGC 2323 and the Initial-Final Mass Relation for Progenitors of 4 to 6.5 M, The Astrophysical Journal, February 2016, 818 (1): 13, Bibcode:2016ApJ...818...84C, arXiv:1601.03053  , doi:10.3847/0004-637X/818/1/84, 84.
^ Paunzen, E.; et al, Photoelectric search for peculiar stars in open clusters. XV. Feinstein 1, NGC 2168, NGC 2323, NGC 2437, NGC 2547, NGC 4103, NGC 6025, NGC 6633, Stock 2, and Trumpler 2, Astronomy & Astrophysics, April 2014, 564: 8, Bibcode:2014A&A...564A..42P, arXiv:1403.3538  , doi:10.1051/0004-6361/201423521, A42.

^ Eight out of ninety degrees south of the celestial equator. Thus its light reaches all parts of the Earth, down to a good minimal cumulation 15° above the horizon, on the unobstructed southern horizons of the 67th parallel north. This rules out Iceland and the north coasts of the two northernmost continents.

外部連結

Messier 50 - at Deep Sky Videos （页面存档备份，存于互联网档案馆）
Messier 50, SEDS Messier pages （页面存档备份，存于互联网档案馆）
M50 Image by Waid Observatory （页面存档备份，存于互联网档案馆）
WikiSky上关于M50 (疏散星團)的内容：DSS2, SDSS, GALEX, IRAS, 氢α, X射线, 天文照片, 天图, 文章和图片

NASA Astronomy Picture of the Day: Open Cluster M50 (28 January 1997)

[Frolov2012-1] 1.0 ^1.1 ^1.2 ^1.3 Frolov, V. N.; et al, Investigation of the open star cluster NGC 2323 (M50) based on the proper motions and photometry of its constituent stars, Astronomy Letters, February 2012, 38 (2): 74–86, Bibcode:2012AstL...38...74F, doi:10.1134/S106377371202003X.

[kharchenko2005-3] 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.

[Thompson2007-4] 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.: 321, 2007, ISBN 978-0596526856

[Claria1998-5] 4.0 ^4.1 ^4.2 ^4.3 ^4.4 Claria, J. J.; et al, Photometric study of the open cluster NGC 2323, Astronomy and Astrophysics Supplement, February 1998, 128: 131–138, Bibcode:1998A&AS..128..131C, doi:10.1051/aas:1998130 

[SIMBAD-6] M 50. SIMBAD. 斯特拉斯堡天文資料中心.

[Sharma2008-7] Sharma, Saurabh; et al, Mass Functions and Photometric Binaries in Nine Open Clusters, The Astronomical Journal, May 2008, 135 (5): 1934–1945, Bibcode:2008AJ....135.1934S, arXiv:0803.0122  , doi:10.1088/0004-6256/135/5/1934.

[Cummings2016-8] Cummings, Jeffrey D.; et al, Two Massive White Dwarfs from NGC 2323 and the Initial-Final Mass Relation for Progenitors of 4 to 6.5 M, The Astrophysical Journal, February 2016, 818 (1): 13, Bibcode:2016ApJ...818...84C, arXiv:1601.03053  , doi:10.3847/0004-637X/818/1/84, 84.

[Paunzen2014-9] Paunzen, E.; et al, Photoelectric search for peculiar stars in open clusters. XV. Feinstein 1, NGC 2168, NGC 2323, NGC 2437, NGC 2547, NGC 4103, NGC 6025, NGC 6633, Stock 2, and Trumpler 2, Astronomy & Astrophysics, April 2014, 564: 8, Bibcode:2014A&A...564A..42P, arXiv:1403.3538  , doi:10.1051/0004-6361/201423521, A42.

[2] Eight out of ninety degrees south of the celestial equator. Thus its light reaches all parts of the Earth, down to a good minimal cumulation 15° above the horizon, on the unobstructed southern horizons of the 67th parallel north. This rules out Iceland and the north coasts of the two northernmost continents.

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