北冕座T

北冕座T（T Coronae Borealis，縮寫T CrB）是位於星座北冕座的一顆再發新星。它最早是由約翰·伯明罕 (天文學家)（英语：John Birmingham (astronomer)）在1866年爆發時發現的，然而它早些時候被觀測到是一顆10等星。它可能在1217年和1787年被觀測到。 北冕座T的星等通常約為10等，接近典型雙筒望遠鏡的極限。 之前曾觀察過它兩次爆發，分別在1866年5月12日和1946年2月9日，視星等分別達到2.0等和3.0等。然而，最近的一篇論文顯示，1866年的爆發可能具有2.5等的峰值範圍，± 0.5。即使在2.5等的峰值星等下，這顆再發新星也比夜空中大約120顆恆星還要暗。它有時被暱稱為「烈焰之星」。 北冕座T是一個 聯星系統，包含一顆巨大的低溫恆星和一顆緻密的高溫恆星。主星是一顆表面溫度較低的紅巨星，它正在將物質轉移到炙熱的伴星上。熾熱的伴星全部隱藏在來自紅巨星的密集物質雲中，是一顆被吸積盤環繞的白矮星。當系統處於寧靜狀態時，紅巨星主導可見光的輸出，系統呈現的恆星光譜為M3的巨星。熾熱的伴星會貢獻一些發射並主導紫外線的輸出。在爆發過程中，白矮星因為熱失控釋放出大量的能量，系統的光度因而暴增 。 該系統的兩顆恆星每228天相互繞行一次。軌道幾乎是圓形的，傾斜角度為67°。 2016年4月20日，天空與望遠鏡雜誌的網站報導，自2015年2月以來，它的亮度從10.5等持續變亮到約9.2等。1938 年，也有類似事件的報導，然後在1946年發生了爆發。到2018年6月，這顆恆星略微變暗，但仍保持著異常高的活動水準。在2023年3月或4月，它變暗至12.3等。1946年爆發的前一年也發生了類似的變暗，這表明它可能會在2024年3月至9月爆發。 Gaia Collaboration; et al. Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties. Astronomy & Astrophysics. November 2016, 595: 23. Bibcode:2016A&A...595A...2G. S2CID 1828208. arXiv:1609.04172 . doi:10.1051/0004-6361/201629512. A2.  Samus, N. N.; Durlevich, O. V.; et al. VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013). VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 2009, 1. Bibcode:2009yCat....102025S.  Shenavrin, V. I.; Taranova, O. G.; Nadzhip, A. E. Search for and study of hot circumstellar dust envelopes. Astronomy Reports. 2011, 55 (1): 31–81. Bibcode:2011ARep...55...31S. S2CID 122700080. doi:10.1134/S1063772911010070.  Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; Levato, H.; Morrell, N. I.; Torres, G.; Udry, S. SB9: The ninth catalogue of spectroscopic binary orbits. Astronomy and Astrophysics. 2004, 424 (2): 727–732. Bibcode:2004A&A...424..727P. S2CID 119387088. arXiv:astro-ph/0406573 . doi:10.1051/0004-6361:20041213.  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 Linford, Justin D.; Chomiuk, Laura; Sokoloski, Jennifer L.; Weston, Jennifer H. S.; Van Der Horst, Alexander J.; Mukai, Koji; Barrett, Paul; Mioduszewski, Amy J.; Rupen, Michael. T CRB: Radio Observations during the 2016-2017 "Super-active" State. The Astrophysical Journal. 2019, 884 (1): 8. Bibcode:2019ApJ...884....8L. S2CID 203593955. arXiv:1909.13858 . doi:10.3847/1538-4357/ab3c62 .  Fekel, Francis C.; Joyce, Richard R.; Hinkle, Kenneth H.; Skrutskie, Michael F. Infrared Spectroscopy of Symbiotic Stars. I. Orbits for Well-Known S-Type Systems. The Astronomical Journal. 2000, 119 (3): 1375. Bibcode:2000AJ....119.1375F. doi:10.1086/301260 .  Stanishev, V.; Zamanov, R.; Tomov, N.; Marziani, P. Hα variability of the recurrent nova T Coronae Borealis. Astronomy and Astrophysics. 2004, 415 (2): 609–616. Bibcode:2004A&A...415..609S. S2CID 3000175. arXiv:astro-ph/0311309 . doi:10.1051/0004-6361:20034623.  Wallerstein, George; Harrison, Tanya; Munari, Ulisse; Vanture, Andrew. The Metallicity and Lithium Abundances of the Recurring Novae T CrB and RS Oph. Publications of the Astronomical Society of the Pacific. 2008, 120 (867): 492. Bibcode:2008PASP..120..492W. S2CID 106406607. doi:10.1086/587965 .  Schaefer, Bradley E. Orbital Periods for Three Recurrent Novae. The Astrophysical Journal. 2009, 697 (1): 721–729. Bibcode:2009ApJ...697..721S. S2CID 16087253. arXiv:0903.1349 . doi:10.1088/0004-637X/697/1/721.  Andrews, Robin George. The Night Sky Will Soon Get ‘a New Star.’ Here’s How to See It. - A nova named T Coronae Borealis lit up the night about 80 years ago, and astronomers say it’s expected to put on another show in the coming months.. The New York Times. 8 March 2024 [9 March 2024]. （原始内容存档于8 March 2024）.  Pettit, Edison. The Light-Curves of T Coronae Borealis. Publications of the Astronomical Society of the Pacific. 1946, 58 (341): 153. Bibcode:1946PASP...58..153P. doi:10.1086/125797 .  Barnard, E. E. Nova T Coronae of 1866. Astrophysical Journal. 1907, 25: 279. Bibcode:1907ApJ....25..279B. doi:10.1086/141446.  The recurrent nova T CrB had prior eruptions observed near December 1787 and October 1217 AD. Journal for the History of Astronomy. [2024-03-21]. （原始内容存档于2024-03-21）.  Evidence of mysterious 'recurring nova' that could reappear in 2024 found in medieval manuscript from 1217. Live Science. [2024-03-21]. （原始内容存档于2024-06-18）.  Sanford, Roscoe F. High-Dispersion Spectrograms of T Coronae Borealis.. Astrophysical Journal. 1949, 109: 81. Bibcode:1949ApJ...109...81S. doi:10.1086/145106 .  Schaefer, Bradley E. Comprehensive Photometric Histories of All Known Galactic Recurrent Novae. The Astrophysical Journal Supplement Series. 2010, 187 (2): 275–373. Bibcode:2010ApJS..187..275S. S2CID 119294221. arXiv:0912.4426 . doi:10.1088/0067-0049/187/2/275.  Vmag<2.5. SIMBAD Astronomical Database. [2010-06-25]. （原始内容存档于2017-02-11）.  A Digital Spectral Classification Atlas, R. O. Gray （页面存档备份，存于互联网档案馆）, 34. Unusual Stellar Spectra III: two emission-line stars Iłkiewicz, Krystian; Mikołajewska, Joanna; Stoyanov, Kiril; Manousakis, Antonios; Miszalski, Brent. Active phases and flickering of a symbiotic recurrent nova T CrB. Monthly Notices of the Royal Astronomical Society. 2016, 462 (3): 2695. Bibcode:2016MNRAS.462.2695I. S2CID 119104759. arXiv:1607.06804 . doi:10.1093/mnras/stw1837.  Luna, GJM; Mukai, K.; Sokoloski, J. L.; Nelson, T.; Kuin, P.; Segreto, A.; Cusumano, G.; Jaque Arancibia, M.; Nuñez, N. E. Dramatic change in the boundary layer in the symbiotic recurrent nova T Coronae Borealis. Astronomy and Astrophysics. 2018, 619 (1): 61. Bibcode:2018A&A...619A..61L. S2CID 119078482. arXiv:1807.01304 . doi:10.1051/0004-6361/201833747.  Is T CrB About to Blow its Top?. Sky & Telescope website. 20 April 2016 [2017-08-06]. （原始内容存档于2019-06-30）.  Schaefer, B.E.; Kloppenborg, B.; Waagen, E.O. Announcing T CrB pre-eruption dip. AAVSO. American Association of Variable Star Observers. [18 January 2024]. （原始内容存档于2024-07-02）.  Todd, Ian. T Coronae Borealis nova event guide and how to prepare. Sky at Night Magazine. BBC. [18 March 2024]. （原始内容存档于2024-03-18）.  Wallerstein, George; Tanya Harrison; Ulisse Munari; Andrew Vanture. The Metallicity and Lithium Abundances of the Recurring Novae T CrB and RS Oph. Publications of the Astronomical Society of the Pacific. 11 May 2008, 120 (867): 492–497. Bibcode:2008PASP..120..492W. S2CID 106406607. doi:10.1086/587965 .  R and T Coronae Borealis: Two Stellar Opposites 互联网档案馆的存檔，存档日期2012-04-06. at Sky & Telescope http://www.daviddarling.info/encyclopedia/B/Blaze_Star.html （页面存档备份，存于互联网档案馆） AAVSO: Quick Look View of AAVSO Observations (get recent magnitude estimates for T CrB)