NGC 2346是位于麒麟座中,靠近天球赤道的一个行星状星云[5],在麒麟座δ的东南东方距离不到1度之处[6]。它被非正式地称为蝴蝶星云[3]。星云明亮而显眼,视星等为9.6[3], 并已被广泛研究。它最显著的特征之一是其异常低温的中心恒星,这是一对光谱联星,以及它不寻常的形状。

NGC 2346
星云
哈伯太空望远镜拍摄的NGC 2346
观测资料: J2000.0 epoch
赤经07h 09m 22.52166s[1]
赤纬−00° 48′ 23.6112″[1]
距离4,760 ly(1,458 pc[1][2] 光年
视星等 (V)9.6[3]
视尺度(V)0.91[4]
星座麒麟座
物理性质
半径2 ly
名称蝴蝶星云、虫子星云[3]
相关条目:星云列表

这个星云呈现双极性,气体流出速度适中,在8〜11km/s的范围内,而中心则由膨胀的分子气体环包围。星云的电子密度约为每立方厘米400。星云的电离是来自联星伴星的紫外线发射的结果[7]。更强的红外辐射来自以16 km/s膨胀的分子带辐射。星云中分子气体的质量估计在0.34〜1.85 M的范围内,并且远大于电离气体的质量[8]

中心恒星是由一颗A型次巨星O型次矮星恒星组成的联星[9]。该系统的轨道周期16.00±0.03[2],也是变光周期[10],可能是由于它周围的轨道上有尘埃。尘埃本身被中心恒星加热,因此NGC 2346在光谱的红外部分异常明亮。当两颗恒星中的一颗演化成红巨星时,它吞没了它的伴星,并从自身的大气层中剥离了一圈物质。当红巨星的核心暴露时,一股快速的恒星风从环的两侧膨胀成两个"气泡"。.

图集

 

参考资料

  1. ^ 1.0 1.1 1.2 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
  2. ^ 2.0 2.1 Brown, Alex J.; Jones, David; Boffin, Henri M. J.; Van Winckel, Hans. On the post-common-envelope central star of the planetary nebula NGC 2346. Monthly Notices of the Royal Astronomical Society. February 2019, 482 (4): 4951–4955. Bibcode:2019MNRAS.482.4951B. arXiv:1810.09764 . doi:10.1093/mnras/sty2986. 
  3. ^ 3.0 3.1 3.2 3.3 Jenkins, D. A. First Light and Beyond: Making a Success of Astronomical Observing. Springer International Publishing. July 28, 2015: 216. ISBN 9783319188515. 
  4. ^ Stanghellini, Letizia; et al. The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale. The Astrophysical Journal. December 10, 2008, 689 (1): 194–202. Bibcode:2008ApJ...689..194S. arXiv:0807.1129 . doi:10.1086/592395. 
  5. ^ NGC 2346: A Butterfly-Shaped Planetary Nebula. Astronomy Picture of the Day. October 28, 2001 [2020-08-28]. (原始内容存档于2010-06-29). 
  6. ^ Sinnott, Roger W.; Perryman, Michael A. C. Millennium Star Atlas 1. Sky Publishing Corporation and the European Space Agency. 1997: 249. ISBN 0-933346-84-0. 
  7. ^ Phillips, J. P.; Cuesta, L. Extinction Mapping of the Bipolar Outflow NGC 2346. The Astronomical Journal. January 2000, 119 (1): 335–341. Bibcode:2000AJ....119..335P. doi:10.1086/301170 . 
  8. ^ Arias, L.; et al. Kinematics of the Molecular Hydrogen from the Planetary Nebula NGC 2346. The Astronomical Journal. December 2001, 122 (6): 3293–3304. Bibcode:2001AJ....122.3293A. doi:10.1086/324446 . 
  9. ^ González-Santamaría, I.; Manteiga, M.; Manchado, A.; Ulla, A.; Dafonte, C.; López Varela, P. Planetary nebulae in Gaia EDR3: Central star identification, properties, and binarity. Astronomy & Astrophysics. 2021, 656: A51. Bibcode:2021A&A...656A..51G. S2CID 237940344. arXiv:2109.12114 . doi:10.1051/0004-6361/202141916. 
  10. ^ Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N. General catalogue of variable stars. Astronomy Reports. 5.1. 2017, 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. 

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