M48

M 48
观测资料 (J2000 历元)
星座	长蛇座
赤经	08h 13m 43.0s
赤纬	-05° 45′ 00″
距离	2,500 ly（770 pc）
视星等 (V)	5.8
视大小 (V)	30′
物理特征
质量	2,366+1,109; −755 M☉
半径	63 ly
估计年龄	450±50 Myr
其他特征	M48, NGC 2548, Cr 179, H IV-22
	相关条目：疏散星团、NGC天体表

M48或梅西耶48，也以NGC 2548为人所知，是位于天球赤道上的星座，长蛇座的一个疏散星团。它位于长蛇座最西端的边界附近，靠近麒麟座^[6]，位于长蛇座最亮的星宿一东方偏南，角距离18° 34′^[7]。这个星团是梅西耶在1771年发现的；但就像他在M47中所犯的相同错误，它没有给出正确的位置。他给出的赤经值是正确的，但是赤纬偏离了5度^[8]，因此人们有时会将发现的功劳归给在1783年看见它的卡罗琳·赫歇尔^[8]，她的侄子约翰·赫歇尔形容它是"一个很好的星团，填补了整个区域；恒星的亮度介于9〜13等，没有更暗的星，但它所处的整个天空却奇形怪状的点缀著无数微小的^[7]。"

在良好的大气条件下，肉眼可以看见M48。它最亮的一颗星是8.3等的HIP 40348^[7]。星团位于离太阳 2,500光年之处^[1]。以恒星等龄线（英语：Stellar isochrone）估计它的年龄是7000400000000000000♠4±1亿年，以自转测年法估计的年龄是7000450000000000000♠4.5±0.5亿年；算是相当一致^[4]。这使得他的年龄介于昴宿星团的一亿年和毕宿星团的六亿五千万年之间。依据铁丰度，[Fe/H]]= 3001370000000000000♠−0.063±0.007 dex，金属丰度若为-1，则表示比太阳少10倍。它比昴宿星团、毕宿星团和鬼宿星团更缺乏金属元素^[9]。

这个星团的潮汐半径为63.3 ± 7.8 ly（19.4 ± 2.4 pc）^[3]，至少有438个成员^[10]和质量为7033470490930000000♠2,366 M_☉^[3]。可能是由于和星系盘的相互作用，这个星团的结构呈现块状的碎片。现在，这个星团被分为三组，每一组都有自己集体的自行^[10]。

参考资料[编辑]

^ ^1.0 ^1.1 ^1.2 ^1.3 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 Mullaney, James, The Herschel Objects and How to Observe Them, Astronomers' Observing Guides, Springer Science & Business Media: 93, 2007, Bibcode:2007hoho.book.....M, ISBN 978-0387681252.
^ ^3.0 ^3.1 ^3.2 ^3.3 Piskunov, A. E.; et al, Tidal radii and masses of open clusters, Astronomy and Astrophysics, January 2008, 477 (1): 165–172, Bibcode:2008A&A...477..165P, doi:10.1051/0004-6361:20078525 .
^ ^4.0 ^4.1 Barnes, Sydney A.; et al, A color-period diagram for the open cluster M 48 (NGC 2548), and its rotational age, Astronomy & Astrophysics, November 2015, 583: 21, Bibcode:2015A&A...583A..73B, arXiv:1511.00554 , doi:10.1051/0004-6361/201526129, A73.
^ M 48. SIMBAD. 斯特拉斯堡天文资料中心.
^ Sinnott, Roger W.; Perryman, Michael A. C., Millennium Star Atlas 2, Sky Publishing Corporation and the European Space Agency: 810, 1997, ISBN 0-933346-83-2.
^ ^7.0 ^7.1 ^7.2 Adam, Len, Imaging the Messier Objects Remotely from Your Laptop, The Patrick Moore Practical Astronomy Series, Springer: 227, 2018, Bibcode:2018imor.book.....A, ISBN 978-3319653853.
^ ^8.0 ^8.1 Houston, Walter Scott, Deep-Sky Wonders, Sky Publishing Corporation, 2005, ISBN 978-1-931559-23-2.
^ Sun, Qinghui; et al, WIYN Open Cluster Study LXXIX. M48 (NGC 2548) I. Radial Velocities, Rotational Velocities, and Metallicities of Stars in the Open Cluster M48 (NGC 2548), The Astronomical Journal, May 2020, 159 (5): 13, Bibcode:2020AJ....159..220S, arXiv:2004.06812 , doi:10.3847/1538-3881/ab83ef, 220.
^ ^10.0 ^10.1 Vicente, Belén; et al, NGC 2548: clumpy spatial and kinematic structure in an intermediate-age Galactic cluster, Monthly Notices of the Royal Astronomical Society, September 2016, 461 (3): 2519–2526, Bibcode:2016MNRAS.461.2519V, arXiv:1606.06044 , doi:10.1093/mnras/stw1487.

外部链接[编辑]

Messier 48, SEDS Messier pages （页面存档备份，存于互联网档案馆）
WikiSky上关于M48的内容：DSS2, SDSS, GALEX, IRAS, 氢α, X射线, 天文照片, 天图, 文章和图片

天球赤道座标： 08^h 13.7^m 00^s，−05° 45′ 00″

[Wu2009a-1] 1.0 ^1.1 ^1.2 ^1.3 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.

[Mullaney2007-2] 2.0 ^2.1 Mullaney, James, The Herschel Objects and How to Observe Them, Astronomers' Observing Guides, Springer Science & Business Media: 93, 2007, Bibcode:2007hoho.book.....M, ISBN 978-0387681252.

[Piskunov2008-3] 3.0 ^3.1 ^3.2 ^3.3 Piskunov, A. E.; et al, Tidal radii and masses of open clusters, Astronomy and Astrophysics, January 2008, 477 (1): 165–172, Bibcode:2008A&A...477..165P, doi:10.1051/0004-6361:20078525 .

[Barnes2015-4] 4.0 ^4.1 Barnes, Sydney A.; et al, A color-period diagram for the open cluster M 48 (NGC 2548), and its rotational age, Astronomy & Astrophysics, November 2015, 583: 21, Bibcode:2015A&A...583A..73B, arXiv:1511.00554 , doi:10.1051/0004-6361/201526129, A73.

[SIMBAD-5] M 48. SIMBAD. 斯特拉斯堡天文资料中心.

[Sinnott_Perryman_1997-6] Sinnott, Roger W.; Perryman, Michael A. C., Millennium Star Atlas 2, Sky Publishing Corporation and the European Space Agency: 810, 1997, ISBN 0-933346-83-2.

[Adam2018-7] 7.0 ^7.1 ^7.2 Adam, Len, Imaging the Messier Objects Remotely from Your Laptop, The Patrick Moore Practical Astronomy Series, Springer: 227, 2018, Bibcode:2018imor.book.....A, ISBN 978-3319653853.

[WSH-8] 8.0 ^8.1 Houston, Walter Scott, Deep-Sky Wonders, Sky Publishing Corporation, 2005, ISBN 978-1-931559-23-2.

[Sun_et_al_2020-9] Sun, Qinghui; et al, WIYN Open Cluster Study LXXIX. M48 (NGC 2548) I. Radial Velocities, Rotational Velocities, and Metallicities of Stars in the Open Cluster M48 (NGC 2548), The Astronomical Journal, May 2020, 159 (5): 13, Bibcode:2020AJ....159..220S, arXiv:2004.06812 , doi:10.3847/1538-3881/ab83ef, 220.

[Vicente2016-10] 10.0 ^10.1 Vicente, Belén; et al, NGC 2548: clumpy spatial and kinematic structure in an intermediate-age Galactic cluster, Monthly Notices of the Royal Astronomical Society, September 2016, 461 (3): 2519–2526, Bibcode:2016MNRAS.461.2519V, arXiv:1606.06044 , doi:10.1093/mnras/stw1487.

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