大熊座SU
大熊座SU （SU UMa）是北天拱極星座大熊座的密接聯星。它是一顆週期性的激變變星，其幅度從峰值的10.8等至基值14.96等不等[2]。依據視差位移，該系統與地球的距離是4.53 mas[1]，相當於719光年。它正以相對於地心每秒27公里的徑向速度遠離地球[3]。
| 觀測資料 曆元 J2000 | |
|---|---|
| 星座 | 大熊座 |
| 星官 | |
| 赤經 | 08h 12m 28.26946s[1] |
| 赤緯 | +62° 36′ 22.4280″[1] |
| 視星等（V） | 10.8 – 14.96[2] |
| 特性 | |
| 變星類型 | 大熊座SU[2] |
| 天體測定 | |
| 徑向速度 (Rv) | +27.0[3] km/s |
| 自行 (μ) | 赤經：+6.582[1] mas/yr 赤緯：−24.538[1] mas/yr |
| 視差 (π) | 4.5347 ± 0.0286[1] mas |
| 距離 | 719 ± 5 ly (221 ± 1 pc) |
| 絕對星等 (MV) | +5.1[4] |
| 軌道[5] | |
| 繞行週期 (P) | 0.076351±0.000043 d |
| 傾斜角 (i) | 42[4]° |
| 近心點 曆元 (T) | 2,446,143.6672±0.0015 HJD |
| 半振幅 (K1) (primary) | 59±7 km s–1 km/s |
| 詳細資料 | |
| 白矮星 | |
| 質量 | 0.8[6] M☉ |
| 溫度 | 28,000[6] K |
| 紅矮星 | |
| 質量 | 0.105[7] M☉ |
| 半徑 | 0.167[7] R☉ |
| 其他命名 | |
| 參考資料庫 | |
| SIMBAD | 資料 |
這顆變星是莫斯科天文台的利迪亞·采拉斯卡亞（L. Ceraski）在1908年發現的[9]。它被分類為雙子座U型變星或矮新星[10]。自1926年以來的觀測顯示，這顆變星經歷了兩種不同類型的噴發：亮度範圍在11.6－12.9星等的短週期，最大值持續約兩天，亮度範圍在10.4－11.8的長週期，最大值延長至13天。後者的事件被稱為"超級最大化" [11]。後續發現類似的矮新星，因此大熊座SU現在是這一子類變星的原型[12]。
這是單譜線的光譜聯星，軌道週期1.83小時[5]。它由白矮星組成，通過吸積盤從伴星那裏獲取物質。這個吸積盤不穩定，會定期的爆發，增加系統的亮度[13]。對於大熊座SU，來自伴星的吸積率是9.8×10−13 M☉·yr−1[14]。在白矮星附近發現X射線發射，在爆發時會下降4倍。理論認為這種發射來自白矮星與其吸積盤間的邊界層[13]。
相關條目
參考資料
- ^ 1.0 1.1 1.2 1.3 1.4 1.5 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中此天體在蓋亞望遠鏡第二批數據發布的記錄
- ^ 2.0 2.1 2.2 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.
- ^ 3.0 3.1 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.
- ^ 4.0 4.1 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 .
- ^ 5.0 5.1 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.
- ^ 6.0 6.1 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.
- ^ 7.0 7.1 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.
- ^ SU UMa. SIMBAD. 斯特拉斯堡天文資料中心.
- ^ 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.
- ^ 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.
- ^ Isles, J. E. SU UMa, 1926-54. Journal of the British Astronomical Association. 1974, 84: 365–373. Bibcode:1974JBAA...84..365I.
- ^ van Paradijs, J. Superoutburst : a general phenomenon in dwarf novae. Astronomy and Astrophysics. September 1983, 125: L16–L18. Bibcode:1983A&A...125L..16V.
- ^ 13.0 13.1 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.
- ^ 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.
進階讀物
- 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.