大熊座SU

大熊座SU （SU UMa）是北天拱极星座大熊座的密接联星。它是一颗周期性的激变变星，其幅度从峰值的10.8等至基值14.96等不等^[2]。依据视差位移，该系统与地球的距离是6992219620597542620♠4.53 mas^[1]，相当于719光年。它正以相对于地心每秒27公里的径向速度远离地球^[3]。

大熊座SU

观测资料 历元 J2000
星座	大熊座
星官
赤经	08h 12m 28.26946s[1]
赤纬	+62° 36′ 22.4280″[1]
视星等（V）	10.8 – 14.96[2]
特性
变星类型	大熊座SU[2]
天体测定
径向速度 (Rv)	+27.0[3] km/s
自行 (μ)	赤经：+6.582[1] mas/yr 赤纬：−24.538[1] mas/yr
视差 (π)	4.5347 ± 0.0286[1] mas
距离	719 ± 5 ly (221 ± 1 pc)
绝对星等 (MV)	+5.1[4]
轨道[5]
绕行周期 (P)	7003659672640000000♠0.076351±0.000043 d
倾斜角 (i)	42[4]°
近心点 历元 (T)	7006244614366720000♠2,446,143.6672±0.0015 HJD
半振幅 (K1) (primary)	7001590000000000000♠59±7 km s–1 km/s
详细资料
白矮星
质量	0.8[6] M☉
温度	28,000[6] K
红矮星
质量	0.105[7] M☉
半径	0.167[7] R☉
其他命名
AAVSO 0803+62、​大熊座SU、​2MASS J08122826+6236224[8]
参考资料库
SIMBAD	资料

这颗变星是莫斯科天文台的利迪亚·采拉斯卡亚（英语：Lidiya Tseraskaya）（L. Ceraski）在1908年发现的^[9]。它被分类为双子座U型变星或矮新星^[10]。自1926年以来的观测显示，这颗变星经历了两种不同类型的喷发：亮度范围在11.6－12.9星等的短周期，最大值持续约两天，亮度范围在10.4－11.8的长周期，最大值延长至13天。后者的事件被称为"超级最大化" ^[11]。后续发现类似的矮新星，因此大熊座SU现在是这一子类变星的原型^[12]。

这是单谱线的光谱联星，轨道周期1.83小时^[5]。它由白矮星组成，通过吸积盘从伴星那里获取物质。这个吸积盘不稳定，会定期的爆发，增加系统的亮度^[13]。对于大熊座SU，来自伴星的吸积率是6987980000000000000♠9.8×10⁻¹³ M_☉·yr^−1[14]。在白矮星附近发现X射线发射，在爆发时会下降4倍。理论认为这种发射来自白矮星与其吸积盘间的边界层^[13]。

相关条目

• 超峰

参考资料

1. 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. Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N. General catalogue of variable stars: Version GCVS 5.1. Astronomy Reports. 2017, 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085.
3. Duflot, M.; et al. Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Radial velocities: The Wilson-Evans-Batten catalogue. Astronomy and Astrophysics Supplement. December 1995, 114: 269. Bibcode:1995A&AS..114..269D.
4. Patterson, Joseph. Distances and absolute magnitudes of dwarf novae: Murmurs of period bounce. Monthly Notices of the Royal Astronomical Society. 2011, 411 (4): 2695–2716. doi:10.1111/j.1365-2966.2010.17881.x .
5. Thorstensen, John R.; et al. A Spectroscopic Study of the Cataclysmic Binary Star SU Ursae Majoris. Astrophysical Journal. October 1986, 309: 721. Bibcode:1986ApJ...309..721T. doi:10.1086/164641.
6. Urban, Joel A; Sion, Edward M. The Dwarf Novae during Quiescence. The Astrophysical Journal. 2006, 642 (2): 1029–1041. Bibcode:2006ApJ...642.1029U. arXiv:astro-ph/0602126 . doi:10.1086/501430.
7. Knigge, Christian; Sion, Edward M. The donor stars of cataclysmic variables. Monthly Notices of the Royal Astronomical Society. 2006, 373 (2): 484–502. Bibcode:2006MNRAS.373..484K. arXiv:astro-ph/0609671 . doi:10.1111/j.1365-2966.2006.11096.x.
8. SU UMa. SIMBAD. 斯特拉斯堡天文资料中心.
9. Ceraski, W. Une variable nouvelle 5.1908 Ursae majoris. Astronomische Nachrichten. February 1908, 177 (11): 173. Bibcode:1908AN....177..173C. doi:10.1002/asna.19081771105.
10. Kraft, Robert P.; Luyten, Willem J. Binary Stars among Cataclysmic Variables. VI. on the Mean Absolute Magnitude of U Geminorum Variables. The Astrophysical Journal. October 1965, 142: 1041. Bibcode:1965ApJ...142.1041K. doi:10.1086/148374.
11. Isles, J. E. SU UMa, 1926-54. Journal of the British Astronomical Association. 1974, 84: 365–373. Bibcode:1974JBAA...84..365I.
12. van Paradijs, J. Superoutburst : a general phenomenon in dwarf novae. Astronomy and Astrophysics. September 1983, 125: L16–L18. Bibcode:1983A&A...125L..16V.
13. Collins, David J.; Wheatley, Peter J. X-ray observations of SU UMa throughout six outbursts. Monthly Notices of the Royal Astronomical Society. March 2010, 402 (3): 1816–1823. Bibcode:2010MNRAS.402.1816C. arXiv:0911.2711 . doi:10.1111/j.1365-2966.2009.16009.x.
14. Zead, I.; et al. Spectral and photometric behavior of SU UMa during quiescence and outburst states. New Astronomy. April 2017, 52: 122–132. Bibcode:2017NewA...52..122Z. doi:10.1016/j.newast.2016.10.010.

进阶读物

• Imada, Akira; et al. Discovery of Superhumps during a Normal Outburst of SU Ursae Majoris. Publications of the Astronomical Society of Japan. October 2012, 64 (5, Letter No.5): 4. Bibcode:2012PASJ...64L...5I. arXiv:1210.1087 . doi:10.1093/pasj/64.5.L5.
• Udalski, A. SU Ursae Majoris: The Perfect Prototype of SU UMa Subclass of Dwarf Novae. Astronomical Journal. July 1990, 100: 226. Bibcode:1990AJ....100..226U. doi:10.1086/115508.