天鹅座V476

**天鹅座V476（V476 Cyg）**
	; 1920天鹅座新星（天鹅座V476）; 周围外壳的RGB复合彩色图像，; 由三个窄频波段制成影像：; 蓝色= 4800Å，绿色= Hα波长为6563 Å，; 红色 = [NII]波长为6583 Å。; 来自圣玛丽亚（Santamaria ）"等人"，; 2020年。
观测资料; 历元 J2000.0
星座	天鹅座
星官
赤经	19h 58m 24.46s
赤纬	+53° 37′ 07.5″
视星等（V）	1.7Max.; 17.09Min.
天体测定
距离	665+107; −53 pc
特性
变星类型	新星
Other designations
	天鹅座V476、1920天鹅座新星、GCRV 12334、AAVSO 1955+53B
参考数据库
SIMBAD	资料

天鹅座V476或1920天鹅座新星是1920年现在天鹅座的一颗新星。它是由英国业余天文学家威廉·弗雷德里克·丹宁于1920年8月20日09：30格林威治标准时间发现的，当时它的亮度为3.7等^[4]。它在1920年8月23日达到了1.7等的峰值亮度^[5]^[6]^[7]。它的静态亮度为17.09等。

天鹅座V476的光变曲线非常不寻常，显示出从最大亮度迅速下降，随后缓慢的近乎线性的衰减。它被归类为非常快的新星^[8]，但尾巴很长。光变曲线呈现出“尘埃蜕降”，快速下降到局部亮度最小值，然后亮度小幅增加，最后是漫长而缓慢的下降。据信，这种尘埃蜕降与从新星中喷射出来物质，因为它远离恒星并冷却形成尘埃的过程相吻合^[9]。

所有新星都由一对紧密的双星组成，一颗白矮星和一颗"施主"恒星相互围绕着旋转。这两颗恒星之间的距离如此贴近，以至于密度较低的供体恒星向白矮星转移了物质。在天鹅座V476的情况下，建立的模型表明白矮星的质量为1.18M_⊙，并且它每年从供体恒星接收6990600000000000000♠6×10⁻¹⁰ M_⊙物质^[10]。而且天鹅座V476比预期的要早得多，已经转变为一颗复发的矮新星^[11]。

在恒星周围可以看到一个类似于行星状星云的小发射星云（壳）。圣玛丽亚（Santamaria）等人检查了1944年，1993年和2018年拍摄的星云图像，发现壳体显然正在膨胀。它略呈椭圆形，长轴和短轴为14.6×13.4弧秒（截至2018年），以每年0.073×0.067弧秒的速度膨胀，这意味着物实际的膨胀率为230×200 km/sec^[1]。令人惊讶的是，1997年使用哈伯太空望远镜对外壳进行成像的尝试没有成功^[12]。

图集[编辑]

天鹅座V476的位置 (红圈)
根据AAVSO数据绘制的天鹅座V476的光变曲线。
两张相隔25年的天鹅座V476周围壳体照片，显示了星云的膨胀。两者都是使用Hα 滤镜拍摄，左图是使用威廉·赫歇耳望远镜，右图是使用北欧光学望远镜（英语：Nordic Optical Telescope）^[1]。

参考资料[编辑]

^ ^1.0 ^1.1 ^1.2 Santamaria, E.; Guerrero, M.A.; Ramos-Larios, G.; Toala, J.A.; Sabin, L.; Rubio, G.; Quino-Mendoza, J.A. Angular Expansion of Nova Shells. The Astrophysical Journal. March 2020, 892 (1): 60 [6 December 2020]. Bibcode:2020ApJ...892...60S. S2CID 211132830. arXiv:2002.06749 . doi:10.3847/1538-4357/ab76c5. （原始内容存档于2023-02-28）.
^ ^2.0 ^2.1 V476 Cyg. SIMBAD. 斯特拉斯堡天文资料中心.
^ Schaefer, Bradley E. The distances to Novae as seen by Gaia (PDF). Monthly Notices of the Royal Astronomical Society. 20 September 2018, 481 (3): 3033–3051 [4 December 2020]. arXiv:1809.00180 . doi:10.1093/mnras/sty2388. （原始内容存档 (PDF)于2022-07-01）.
^ Denning, W.F. Estimated magnitudes of Nova Cygni (1920). Astronomische Nachrichten. September 1920, 211 (22): 419 [4 December 2020]. Bibcode:1920AN....211..419D. doi:10.1002/asna.19202112205. （原始内容存档于2022-09-15）.
^ Download Data. AAVSO. [4 December 2020]. （原始内容存档于2023-03-15）.
^ Warner, B. Where have all the novae gone?. Astronomy & Geophysics. February 2006, 47 (1): 29–32 [30 November 2020]. Bibcode:2006A&G....47a..29W. doi:10.1111/j.1468-4004.2006.47129.x. （原始内容存档于2022-09-15）.
^ Beech, M. The Makings of Meteor Astronomy: Part XVII. W.F. Denning and Comets, Nebulae, and Novae. WGN, Journal of the International Meteor Organization. 1998, 26 (6): 268–272 [30 November 2020]. Bibcode:1998JIMO...26..268B. （原始内容存档于2022-09-15）.
^ Slavin, A.J.; O'Brien, T.J.; Dunlop, J.S. A deep optical imaging study of the nebular remnants of classical novae. Monthly Notices of the Royal Astronomical Society. September 1995, 276 (2): 353–371 [4 December 2020]. doi:10.1093/mnras/276.2.353 . （原始内容存档于2022-06-19）.
^ Strope, Richard J.; Schaefer, Bradley E.; Henden, Arne A. Catalog of 93 Nova Light Curves: Classification and Properties (PDF). The Astronomical Journal. July 2010, 140 (1): 34–62 [5 December 2020]. Bibcode:2010AJ....140...34S. S2CID 118537823. arXiv:1004.3698 . doi:10.1088/0004-6256/140/1/34. （原始内容存档 (PDF)于2022-06-24）.
^ Shara, Michael M.; Prialnik, Dina; Hillman, Yael; Kovetz, Attay. The Masses and Accretion Rates of White Dwarfs in Classical and Recurrent Novae. The Astrophysical Journal. June 2018, 860 (2): 110 [4 December 2020]. Bibcode:2018ApJ...860..110S. S2CID 55851634. arXiv:1804.06880 . doi:10.3847/1538-4357/aabfbd. （原始内容存档于2022-12-25）.
^ Kato, Taichi Kato. V476 Cyg (Nova Cyg 1920) is currently a dwarf nova — first such an object in the period gap? (PDF). Variable Star Bulletin (Variable Star Observers League in Japan (VSOLJ)). 2022, (95) [2022-09-15]. （原始内容存档 (PDF)于2022-03-15）.
^ Gill, C.D.; O'Brien, T.J. Hubble Space Telescope imaging and ground-based spectroscopy of old nova shells - I. FH Ser, V533 Her, BT Mon, DK Lac and V476 Cyg. Monthly Notices of the Royal Astronomical Society. May 2000, 314 (1): 175–182. Bibcode:2000MNRAS.314..175G. arXiv:astro-ph/0001092 . doi:10.1046/j.1365-8711.2000.03342.x .

外部链接[编辑]

[sant-1] 1.0 ^1.1 ^1.2 Santamaria, E.; Guerrero, M.A.; Ramos-Larios, G.; Toala, J.A.; Sabin, L.; Rubio, G.; Quino-Mendoza, J.A. Angular Expansion of Nova Shells. The Astrophysical Journal. March 2020, 892 (1): 60 [6 December 2020]. Bibcode:2020ApJ...892...60S. S2CID 211132830. arXiv:2002.06749 . doi:10.3847/1538-4357/ab76c5. （原始内容存档于2023-02-28）.

[simbad-2] 2.0 ^2.1 V476 Cyg. SIMBAD. 斯特拉斯堡天文资料中心.

[brad-3] Schaefer, Bradley E. The distances to Novae as seen by Gaia (PDF). Monthly Notices of the Royal Astronomical Society. 20 September 2018, 481 (3): 3033–3051 [4 December 2020]. arXiv:1809.00180 . doi:10.1093/mnras/sty2388. （原始内容存档 (PDF)于2022-07-01）.

[denn1-4] Denning, W.F. Estimated magnitudes of Nova Cygni (1920). Astronomische Nachrichten. September 1920, 211 (22): 419 [4 December 2020]. Bibcode:1920AN....211..419D. doi:10.1002/asna.19202112205. （原始内容存档于2022-09-15）.

[aavs-5] Download Data. AAVSO. [4 December 2020]. （原始内容存档于2023-03-15）.

[warn-6] Warner, B. Where have all the novae gone?. Astronomy & Geophysics. February 2006, 47 (1): 29–32 [30 November 2020]. Bibcode:2006A&G....47a..29W. doi:10.1111/j.1468-4004.2006.47129.x. （原始内容存档于2022-09-15）.

[beec-7] Beech, M. The Makings of Meteor Astronomy: Part XVII. W.F. Denning and Comets, Nebulae, and Novae. WGN, Journal of the International Meteor Organization. 1998, 26 (6): 268–272 [30 November 2020]. Bibcode:1998JIMO...26..268B. （原始内容存档于2022-09-15）.

[slav-8] Slavin, A.J.; O'Brien, T.J.; Dunlop, J.S. A deep optical imaging study of the nebular remnants of classical novae. Monthly Notices of the Royal Astronomical Society. September 1995, 276 (2): 353–371 [4 December 2020]. doi:10.1093/mnras/276.2.353 . （原始内容存档于2022-06-19）.

[stro-9] Strope, Richard J.; Schaefer, Bradley E.; Henden, Arne A. Catalog of 93 Nova Light Curves: Classification and Properties (PDF). The Astronomical Journal. July 2010, 140 (1): 34–62 [5 December 2020]. Bibcode:2010AJ....140...34S. S2CID 118537823. arXiv:1004.3698 . doi:10.1088/0004-6256/140/1/34. （原始内容存档 (PDF)于2022-06-24）.

[shar-10] Shara, Michael M.; Prialnik, Dina; Hillman, Yael; Kovetz, Attay. The Masses and Accretion Rates of White Dwarfs in Classical and Recurrent Novae. The Astrophysical Journal. June 2018, 860 (2): 110 [4 December 2020]. Bibcode:2018ApJ...860..110S. S2CID 55851634. arXiv:1804.06880 . doi:10.3847/1538-4357/aabfbd. （原始内容存档于2022-12-25）.

[Kato-11] Kato, Taichi Kato. V476 Cyg (Nova Cyg 1920) is currently a dwarf nova — first such an object in the period gap? (PDF). Variable Star Bulletin (Variable Star Observers League in Japan (VSOLJ)). 2022, (95) [2022-09-15]. （原始内容存档 (PDF)于2022-03-15）.

[gill-12] Gill, C.D.; O'Brien, T.J. Hubble Space Telescope imaging and ground-based spectroscopy of old nova shells - I. FH Ser, V533 Her, BT Mon, DK Lac and V476 Cyg. Monthly Notices of the Royal Astronomical Society. May 2000, 314 (1): 175–182. Bibcode:2000MNRAS.314..175G. arXiv:astro-ph/0001092 . doi:10.1046/j.1365-8711.2000.03342.x .

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外部链接[编辑]