Astronomy:T Coronae Borealis

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T Coronae Borealis
TCrBLocation.png
Location of T Coronae Borealis (circled in red)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Corona Borealis
Right ascension  15h 59m 30.1622s[1]
Declination 25° 55′ 12.613″[1]
Apparent magnitude (V) 2.0–10.8[2]
Characteristics
Evolutionary stage Red giant + white dwarf
Spectral type M3III+p[3]
Variable type recurrent nova[2]
Astrometry
Radial velocity (Rv)−27.79[4] km/s
Proper motion (μ) RA: −4.220[5] mas/yr
Dec.: 12.364[5] mas/yr
Parallax (π)1.2127 ± 0.0488[5] mas
Distance806+34
−30[6] pc
Orbit
Period (P)227.8 d[7]
Semi-major axis (a)0.54 astronomical unit|AU[6]
Eccentricity (e)0.0[7]
Inclination (i)67[8]°
Details
Red giant
Mass1.12[6] M☉
Radius75[8] R☉
Luminosity655[9] L☉
Surface gravity (log g)2.0[10] cgs
Temperature3,600[10] K
White dwarf
Mass1.37[6] M☉
Luminosity~100[8] L☉
Other designations
Database references
SIMBADdata

T Coronae Borealis (T CrB), is a recurring nova in the constellation Corona Borealis. It was first discovered in outburst in 1866 by John Birmingham,[11] although it had been observed earlier as a 10th magnitude star.[12]

Description

The light curve of T Coronae Borealis during the time surrounding its 1946 eruption, plotted from AAVSO data

T CrB normally has a magnitude of about 10, which is near the limit of typical binoculars. It has been seen to outburst twice, reaching magnitude 2.0 on May 12, 1866 and magnitude 3.0 on February 9, 1946,[13] although a more recent paper shows the 1866 outburst with a possible peak range of magnitude 2.5 ± 0.5.[14] Even when at peak magnitude of 2.5, this recurrent nova is dimmer than about 120 stars in the night sky.[15] It is sometimes nicknamed the Blaze Star.[16]

T CrB is a binary system containing a large cool component and a smaller hot component. The cool component is a red giant which is transferring material to the hot component. The hot component is a white dwarf surrounded by an accretion disc, all hidden inside a dense cloud of material from the red giant. When the system is quiescent, the red giant dominates the visible light output and the system appears as an M3 giant. The hot component contributes some emission and dominates the ultraviolet output. During outbursts, the transfer of material to the hot component increases greatly, the hot component expands, and the luminosity of the system increases.[6][8][17] [18]

AAVSO light curve of recurrent nova T CrB from 1 Jan 2008 to 17 Nov 2010, showing the pulsations of the red giant primary. Up is brighter and down is fainter. Day numbers are Julian day.

The two components of the system orbit each other every 228 days. The orbit is almost circular and is inclined at an angle of 67°. The stars are separated by 0.54 astronomical unit|AU.[6]

2016-present activity

On 20 April 2016, the Sky and Telescope website reported a sustained brightening since February 2015 from magnitude 10.5 to about 9.2. A similar event was reported in 1938, shortly before the 1946 outburst.[19] By June 2018, the star had dimmed slightly but still remained at an unusually high level of activity. In March or April 2023, it dimmed to magnitude 12.3.[20] A similar dimming occurred in the year before the 1945 outburst, indicating that it will likely erupt in the first half of 2024.

References

  1. ↑ 1.0 1.1 Gaia Collaboration et al. (November 2016). "Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties". Astronomy & Astrophysics 595: 23. doi:10.1051/0004-6361/201629512. A2. Bibcode: 2016A&A...595A...2G. 
  2. ↑ 2.0 2.1 Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1. Bibcode: 2009yCat....102025S. 
  3. ↑ Shenavrin, V. I.; Taranova, O. G.; Nadzhip, A. E. (2011). "Search for and study of hot circumstellar dust envelopes". Astronomy Reports 55 (1): 31–81. doi:10.1134/S1063772911010070. Bibcode: 2011ARep...55...31S. 
  4. ↑ Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; Levato, H.; Morrell, N. I.; Torres, G. et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics 424 (2): 727–732. doi:10.1051/0004-6361:20041213. Bibcode: 2004A&A...424..727P. 
  5. ↑ 5.0 5.1 5.2 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Linford, Justin D.; Chomiuk, Laura; Sokoloski, Jennifer L.; Weston, Jennifer H. S.; Van Der Horst, Alexander J.; Mukai, Koji; Barrett, Paul; Mioduszewski, Amy J. et al. (2019). "T CRB: Radio Observations during the 2016-2017 "Super-active" State". The Astrophysical Journal 884 (1): 8. doi:10.3847/1538-4357/ab3c62. Bibcode: 2019ApJ...884....8L. 
  7. ↑ 7.0 7.1 Fekel, Francis C.; Joyce, Richard R.; Hinkle, Kenneth H.; Skrutskie, Michael F. (2000). "Infrared Spectroscopy of Symbiotic Stars. I. Orbits for Well-Known S-Type Systems". The Astronomical Journal 119 (3): 1375. doi:10.1086/301260. Bibcode: 2000AJ....119.1375F. 
  8. ↑ 8.0 8.1 8.2 8.3 Stanishev, V.; Zamanov, R.; Tomov, N.; Marziani, P. (2004). "Hα variability of the recurrent nova T Coronae Borealis". Astronomy and Astrophysics 415 (2): 609–616. doi:10.1051/0004-6361:20034623. Bibcode: 2004A&A...415..609S. 
  9. ↑ Schaefer, Bradley E. (2009). "Orbital Periods for Three Recurrent Novae". The Astrophysical Journal 697 (1): 721–729. doi:10.1088/0004-637X/697/1/721. Bibcode: 2009ApJ...697..721S. 
  10. ↑ 10.0 10.1 Wallerstein, George; Harrison, Tanya; Munari, Ulisse; Vanture, Andrew (2008). "The Metallicity and Lithium Abundances of the Recurring Novae T CrB and RS Oph". Publications of the Astronomical Society of the Pacific 120 (867): 492. doi:10.1086/587965. Bibcode: 2008PASP..120..492W. 
  11. ↑ Pettit, Edison (1946). "The Light-Curves of T Coronae Borealis". Publications of the Astronomical Society of the Pacific 58 (341): 153. doi:10.1086/125797. Bibcode: 1946PASP...58..153P. 
  12. ↑ Barnard, E. E. (1907). "Nova T Coronae of 1866". Astrophysical Journal 25: 279. doi:10.1086/141446. Bibcode: 1907ApJ....25..279B. 
  13. ↑ Sanford, Roscoe F. (1949). "High-Dispersion Spectrograms of T Coronae Borealis.". Astrophysical Journal 109: 81. doi:10.1086/145106. Bibcode: 1949ApJ...109...81S. 
  14. ↑ Schaefer, Bradley E. (2010). "Comprehensive Photometric Histories of All Known Galactic Recurrent Novae". The Astrophysical Journal Supplement Series 187 (2): 275–373. doi:10.1088/0067-0049/187/2/275. Bibcode: 2010ApJS..187..275S. 
  15. ↑ "Vmag<2.5". SIMBAD Astronomical Database. http://simbad.u-strasbg.fr/simbad/sim-sam?Criteria=Vmag%3C2.5. Retrieved 2010-06-25. 
  16. ↑ A Digital Spectral Classification Atlas, R. O. Gray, 34. Unusual Stellar Spectra III: two emission-line stars
  17. ↑ Iłkiewicz, Krystian; Mikołajewska, Joanna; Stoyanov, Kiril; Manousakis, Antonios; Miszalski, Brent (2016). "Active phases and flickering of a symbiotic recurrent nova T CrB". Monthly Notices of the Royal Astronomical Society 462 (3): 2695. doi:10.1093/mnras/stw1837. Bibcode: 2016MNRAS.462.2695I. 
  18. ↑ Luna, GJM; Mukai, K.; Sokoloski, J. L.; Nelson, T.; Kuin, P.; Segreto, A.; Cusumano, G.; Jaque Arancibia, M. et al. (2018). "Dramatic change in the boundary layer in the symbiotic recurrent nova T Coronae Borealis". Astronomy and Astrophysics 619 (1): 61. doi:10.1051/0004-6361/201833747. Bibcode: 2018A&A...619A..61L. 
  19. ↑ "Is T CrB About to Blow its Top?". Sky & Telescope website. 20 April 2016. http://www.skyandtelescope.com/observing/whats-up-with-t-crb04202016. Retrieved 2017-08-06. 
  20. ↑ Schaefer, B.E.; Kloppenborg, B.; Waagen, E.O.. "Announcing T CrB pre-eruption dip". American Association of Variable Star Observers. https://www.aavso.org/news/t-crb-pre-eruption-dip. 

Further reading

External links



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