T Coronae Borealis

From testwiki
Jump to navigation Jump to search

Template:Short description Template:DistinguishTemplate:Redirect-distinguish Template:Use American English Template:Use mdy dates Template:Starbox begin Template:Starbox image Template:Starbox observe Template:Starbox character Template:Starbox astrometry Template:Starbox orbit Template:Starbox detail Template:Starbox catalog Template:Starbox reference Template:Starbox end

T Coronae Borealis is a binary star and a recurrent nova about Template:Convert away in the constellation Corona Borealis.[1] Template:Nobr is its variable-star designation and the name most frequently used in the astronomical literature, but it also has the official proper name Blaze Star. The system was first observed in outburst inTemplate:Nbsp1866 by John Birmingham,[2] but had been observed earlier in quiescence as a [[Apparent magnitude|10thTemplate:Nbspmagnitude star]].[3] It may have been observed inTemplate:Nbsp1217 and inTemplate:Nbsp1787 as well.[4][5] In FebruaryTemplate:Nbsp1946, the flare-up was discovered independently by three observers: the Soviet amateur astronomer A. S. Kamenchuk, the 15-year-old schoolboy Michael Woodman from Wales, and the British variable star observer N. F. H. Knight.[6] This led to the theory that the star flares every 80Template:Nbspyears[7] with the next nova expected to occur before 2027. Its apparent magnitude varies between 2.0 in outburst and 10.8 in quiescence, representing about a 3300-fold change in brightness. T Coronae Borealis enters solar conjunction and becomes hidden by the Sun's glare in late November.

Nomenclature

T Coronae Borealis (abbreviated TTemplate:NbspCrB or unofficially T Cor Bor)[8] is the star's variable star designation and is its most commonly used name. It also has the Bright Star Catalogue designation HR 5958 and the Henry Draper Catalogue designation HD 143454.[9]

The proper name Blaze Star[10] has been used since its outburst in 1866, and was officially approved by the IAU Working Group on Star Names on 22 September 2025.[11]

Description

dot graph
The light curve of TTemplate:NbspCoronae Borealis during the time surrounding its 1946Template:Nbsperuption, plotted from AAVSOTemplate:Nbspdata

T CrB normally has a magnitude of aboutTemplate:Nbsp10, which is near the limit of typical binoculars. Two well-documented outbursts have been observed, reaching magnitudeTemplate:Nbsp2.0 on MayTemplate:Nbsp12, 1866 and magnitudeTemplate:Nbsp3.0 on FebruaryTemplate:Nbsp9, 1946,[12] though a more recent paper shows the 1866Template:Nbspoutburst with a possible peak range of magnitudeTemplate:NbspTemplate:Val.[13] When at peak magnitude ofTemplate:Nbsp2.5, this recurrent nova is dimmer than about 100Template:Nbspbrightest stars in the night sky,[14] but easily visible to the naked eye.

diagram of a red giant star and smaller companion star which is accreting gas from its companion
Diagram of TTemplate:NbspCoronae Borealis based on a description given by Kraft[15] using the updated mass ratio given by Stanishev[16]

T CrB is a binary system containing a large cool component and a smaller hot component. The cool component is a red giant that transfers material to the hot component.[15] The hot component, which initially was the most massive and brightest of the two stars, is now 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 [[Stellar classification|M3Template:Nbspgiant]]. 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 overall luminosity of the system increases by orders of magnitude.[16][17][18][19]

Image of T Crb on 23 June 2026
TTemplate:NbspCoronae Borealis imaged on 23 June 2026 with a Unistellar 114mm smart telescope (north is towards top right, field of view about 0.5°)

[[File:T-CrB-Lightcurve-AAVSO.gif|upright=1.2|thumb|left|alt=dot graph|AAVSO light curve of recurrent nova TTemplate:NbspCrB from JanTemplate:Nbsp1, 2008 to NovTemplate:Nbsp17, 2010, showing rotating ellipsoidal variability. Up is brighter and down is fainter. Day numbers are [[Julian day|JulianTemplate:Nbspday]].]] The two components of the system orbit each other every Template:Val. The orbit is almost circular and is inclined at an angle ofTemplate:Nbsp61.5°. The separation between the components isTemplate:NbspTemplate:Convert.[20]

2016–present activity

On April 20, 2016, Sky & Telescope reported a sustained brightening since FebruaryTemplate:Nbsp2015 from magnitudeTemplate:Nbsp10.5 to aboutTemplate:Nbsp9.2. A similar event was reported inTemplate:Nbsp1938, 8 years before theTemplate:Nbsp1946 outburst.[21] By JuneTemplate:Nbsp2018, the star had dimmed slightly but still remained at an unusually high level of activity. By mid-2023, it had faded byTemplate:Nbsp0.35 magnitude or about 28%;Template:Efn its lowest brightness seen sinceTemplate:Nbsp2016.[22] A similar dimming occurred in the year before the 1946Template:Nbspoutburst,[23] leading some to predict an eruption before SeptemberTemplate:Nbsp2024.[24] The eruption has repeatedly been predicted to be imminent, but no nova has been observed as of October 2026 and several of the predictions have already lapsed.[23]

Outburst predictions

Template:Outdated as of Predictions of the next nova (in order of when the prediction was made): Template:Flowlist

Template:Endflowlist Template:Clear

Notes

Template:Notelist

References

Template:Reflist

Further reading

Template:2025 in space Template:Stars of Corona Borealis

  1. ↑ Template:Cite news
  2. ↑ Template:Cite journal
  3. ↑ Template:Cite journal
  4. ↑ Template:Cite journal
  5. ↑ Template:Cite web
  6. ↑ Template:Cite journal
  7. ↑ Template:Cite web
  8. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named "Starrfield2024".
  9. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named "simbad".
  10. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named "Proctor1897".
  11. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named "IAU-CSN-new".
  12. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named "Sanford1949".
  13. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named "Schaefer2009".
  14. ↑ Template:Cite web
  15. ↑ 15.0 15.1 Cite error: Invalid <ref> tag; no text was provided for refs named "Kraft1958".
  16. ↑ 16.0 16.1 Cite error: Invalid <ref> tag; no text was provided for refs named "stanishev".
  17. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named "linford".
  18. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named "ilkiewicz".
  19. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named "luna".
  20. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named "Munari2025".
  21. ↑ Template:Cite web
  22. ↑ Template:Cite web
  23. ↑ 23.0 23.1 Template:Cite web
  24. ↑ Template:Cite web
  25. ↑ Template:Cite journal
  26. ↑ Template:Cite journal
  27. ↑ Template:Cite journal
  28. ↑ Template:Cite journal
  29. ↑ Template:Cite journal
  30. ↑ Template:Cite journal
Retrieved from "https://en.wiki.beta.math.wmflabs.org/w/index.php?title=T_Coronae_Borealis&oldid=12412"