T Coronae Borealis

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T Coronae Borealis
TCrBLocation.png
Location of T Coronae Borealis (circled in red)
Observation data
Epoch J2000       Equinox J2000
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  mas [5]
Distance 806+34
−30 [6]   pc
Orbit
Period (P)227.8  d [7]
Semi-major axis (a)0.54  AU [6]
Eccentricity (e)0.0 [7]
Inclination (i)67 [8] °
Details
Red giant
Mass 1.12 [6]   M☉
Radius 75 [8]   R☉
Luminosity 655 [9]   L☉
Surface gravity (log g)2.0 [10]   cgs
Temperature 3,600 [10]   K
White dwarf
Mass 1.37 [6]   M☉
Luminosity~100 [8]   L☉
Other designations
BD+26° 2765, HD  143454, HIP  78322, SAO  84129, 2MASS J15593015+2555126
Database references
SIMBAD data

T Coronae Borealis (T CrB), nicknamed the Blaze star, is a recurrent nova in the constellation Corona Borealis. [11] It was first discovered in outburst in 1866 by John Birmingham, [12] although it had been observed earlier as a 10th magnitude star. [13] It may have been observed in 1217 and in 1787 as well. [14] [15] It is expected to undergo an outburst again in 2024.

Contents

Description

The light curve of T Coronae Borealis during the time surrounding its 1946 eruption, plotted from AAVSO data TCrBLightCurve.png
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. Outbursts have been seen twice, reaching magnitude 2.0 on May 12, 1866 and magnitude 3.0 on February 9, 1946, [16] although a more recent paper shows the 1866 outburst with a possible peak range of magnitude 2.5 ± 0.5. [17] Even when at peak magnitude of 2.5, this recurrent nova is dimmer than about 120 stars in the night sky. [18] It is sometimes nicknamed the Blaze Star. [19]

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] [20] [21]

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. T-CrB-Lightcurve-AAVSO.gif
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  AU . [6]

2016–present activity

On 20 April 2016, the Sky & Telescope website reported a sustained brightening since February 2015 from magnitude 10.5 to about 9.2. A similar event was reported in 1938, followed by another outburst in 1946. [22] 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. [23] A similar dimming occurred in the year before the 1946 outburst, indicating that it will likely erupt between April and September 2024. [24]

Related Research Articles

<span class="mw-page-title-main">Corona Borealis</span> Constellation in the northern celestial hemisphere

Corona Borealis is a small constellation in the Northern Celestial Hemisphere. It is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and remains one of the 88 modern constellations. Its brightest stars form a semicircular arc. Its Latin name, inspired by its shape, means "northern crown". In classical mythology Corona Borealis generally represented the crown given by the god Dionysus to the Cretan princess Ariadne and set by her in the heavens. Other cultures likened the pattern to a circle of elders, an eagle's nest, a bear's den or a smokehole. Ptolemy also listed a southern counterpart, Corona Australis, with a similar pattern.

<span class="mw-page-title-main">R Coronae Borealis</span> Variable star in the constellation Corona Borealis

R Coronae Borealis is a low-mass yellow supergiant star in the constellation of Corona Borealis. It is the prototype of the R Coronae Borealis variable of variable stars, which fade by several magnitudes at irregular intervals. R Coronae Borealis itself normally shines at approximately magnitude 6, just about visible to the naked eye, but at intervals of several months to many years fades to as faint as 15th magnitude. Over successive months it then gradually returns to its normal brightness, giving it the nickname "reverse nova", after the more common type of star which rapidly increases in brightness before fading.

<span class="mw-page-title-main">Rho Coronae Borealis</span> Star in the constellation Corona Borealis

Rho Coronae Borealis is a yellow dwarf star 57.1 light-years away in the constellation of Corona Borealis. The star is thought to be similar to the Sun with nearly the same mass, radius, and luminosity. It is orbited by four known exoplanets.

<span class="mw-page-title-main">DY Persei</span> Variable carbon star in the constellation Perseus

DY Persei is a variable star and carbon star in the Perseus constellation. At maximum it is 11th magnitude and at its faintest it drops to 16th magnitude. DY Persei is the prototype of the very rare DY Persei class of variables that pulsate like red variables but also fade from sight like R Coronae Borealis variables.

<span class="mw-page-title-main">U Scorpii</span> Recurrent nova system first seen in 1863

U Scorpii is a recurrent nova system; one of 10 known recurring novae in the Milky Way galaxy. Located near the northern edge of the constellation Scorpius it normally has a magnitude of 18, but reaches a magnitude of about 8 during outbursts. Outbursts have been observed in 1863, 1906, 1936, 1979, 1987, 1999, 2010, and 2022.

<span class="mw-page-title-main">Gamma Coronae Borealis</span> Star in the constellation Corona Borealis

Gamma Coronae Borealis, Latinized from γ Coronae Borealis, is a binary star system in the northern constellation of Corona Borealis. It is visible to the naked eye with an apparent visual magnitude of 3.83. Based upon an annual parallax shift of 22.33 mas as seen from Earth, it is located about 146 light years from the Sun. The system is moving closer to the Sun with a radial velocity of about −15 km/s.

<span class="mw-page-title-main">Epsilon Coronae Borealis</span> Multiple star system in the constellation Corona Borealis

Epsilon Coronae Borealis, Latinized from ε Coronae Borealis, is a multiple star system in the constellation Corona Borealis located around 230 light-years from the Solar System. It shines with a combined apparent magnitude of 4.13, meaning it is visible to the unaided eye in all night skies except those brightly lit in inner city locations. It is an orange giant around 1.7 times as massive as the Sun of spectral type K2III, which has exhausted its core fuel supply of hydrogen and swollen to 21 times the Sun's diameter and 151 times its luminosity. That is, Epsilon Coronae Borealis's diameter is about one-quarter of Mercury's orbit. Its surface temperature has been calculated to be 4365 ± 9 K, or 4406 ± 15 K. It is thought to be around 1.74 billion years old.

<span class="mw-page-title-main">Delta Coronae Borealis</span> Yellow giant star in the constellation Corona Borealis

Delta Coronae Borealis, Latinized from δ Coronae Borealis, is a variable star in the constellation Corona Borealis. Its apparent magnitude varies regularly between apparent magnitude 4.57 and 4.69, and it is around 170 light-years distant.

Tau Coronae Borealis, Latinized from τ Coronae Borealis, is a possible astrometric and spectroscopic binary star system in the northern constellation of Corona Borealis. It is visible to the naked eye with an apparent visual magnitude of 4.76.

Iota Coronae Borealis, Latinized from ι Coronae Borealis, is a binary star system in the constellation Corona Borealis. It is visible to the naked eye with a combined apparent visual magnitude of is 4.96. Based upon an annual parallax shift of 10.46 mas as seen from the Earth, it is located about 312 light years from the Sun.

Kappa1 Coronae Australis, Latinized from κ1 Coronae Australis, is a star located in the southern constellation Corona Australis. It has an apparent magnitude of 6.17, placing it near the limit for naked eye visibility.

<span class="mw-page-title-main">Lambda Coronae Borealis</span> Yellow-white hued star in the constellation Corona Borealis

Lambda Coronae Borealis, its name Latinised from λ Coronae Borealis, is a single star in the northern constellation of Corona Borealis. In publications it is also identified as HR 5936 and HD 142908. It has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.43. The star is located at a distance of 136 light years based on parallax, but is drifting closer with a radial velocity of −12 km/s.

Mu Coronae Borealis, Latinized from μ Coronae Borealis, is a solitary, ruby-hued star located in the northern constellation of Corona Borealis. It is faintly visible to the naked eye, having an apparent visual magnitude of 5.12. Based upon an annual parallax shift of 5.27 mas, it is located roughly 620 light years from the Sun. This is an evolved red giant star with a stellar classification of M1.5 IIIb. It is currently on the asymptotic giant branch and is a variable star of uncertain type, showing a change in brightness with an amplitude of 0.0147 magnitude and a frequency of 0.02455 cycles per day, or 40.7 days/cycle. On average, it is radiating 932 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,889 K.

<span class="mw-page-title-main">RY Sagittarii</span> Yellow supergiant star in the constellation Sagittarius

RY Sagittarii is a yellow supergiant and an R Coronae Borealis type variable star in the constellation Sagittarius. Although it ostensibly has the spectrum of a G-type star, it differs markedly from most in that it has almost no hydrogen and much carbon.

<span class="mw-page-title-main">RS Telescopii</span> Star in the constellation Telescopium

RS Telescopii, abbreviated RS Tel, is a variable star in the southern constellation of Telescopium. It is a dim star with an apparent visual magnitude of 10.67, which is much too faint to be visible without a telescope. The variability of this star was discovered by Evelyn F. Leland and announced by Edward C. Pickering in 1910. It was first studied by Cecilia H. Payne in 1928 at the Harvard College Observatory.

<span class="mw-page-title-main">V Coronae Australis</span> Variable star in the constellation Corona Australis

V Coronae Australis is a R Coronae Borealis variable (RCB) star in the constellation Corona Australis. These are extremely hydrogen-deficient supergiants thought to have arisen as the result of the merger of two white dwarfs; fewer than 100 have been discovered as of 2012. V Coronae Australis dimmed in brightness from 1994 to 1998.

<span class="mw-page-title-main">WX Coronae Australis</span> Variable star in the constellation Corona Australis

WX Coronae Australis is an R Coronae Borealis star in the constellation Corona Australis, one of the brightest examples of this extremely rare class of variable star. Despite the rarity, Corona Australis hosts another R CrB star, V Coronae Australis.

<span class="mw-page-title-main">Sigma Coronae Borealis</span> Star in the constellation Corona Borealis

Sigma Coronae Borealis is a star system in the constellation of Corona Borealis. It is a quintuple star system containing three sunlike main-sequence stars and two other low-mass stars. The combined visual magnitude is 5.3 and the system lies 74 light years from Earth. σ CrB A is the variable star TZ Coronae Borealis.

<span class="mw-page-title-main">S Apodis</span> Variable star in the constellation Apus

S Apodis, also known as HD 133444 is a variable star located in the southern circumpolar constellation Apus. It has an apparent magnitude ranging from 9.6 to 17, which is below the limit for naked eye visibility. The object is located relatively far at a distance of approximately 15,000 light years based on Gaia DR3 parallax measurements, but it is drifting closer with a heliocentric radial velocity of −75 km/s.

<span class="mw-page-title-main">V4332 Sagittarii</span>

V4332 Sagittarii is a nova-like event in the constellation of Sagittarius. It was discovered February 24, 1994 at an apparent visual magnitude of 8.9 by Japanese amateur astronomer Minoru Yamamoto from Okazaki, Aichi, then confirmed by K. Hirosawa. Initially designated Nova Sagittarii 1994 #1, it was given the variable star designation V4332 Sgr. A spectra of the event taken March 4 lacked the characteristic features of a classical nova, with the only emission lines being of the Balmer series. Subsequent spectra showed a rapid decline in luminosity and a change of spectral type over a period of five days. By 2003, the object was ~1500 times less luminous than at peak magnitude and showed a spectrum of an M-type star.

References

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  8. 1 2 3 4 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. arXiv: astro-ph/0311309 . Bibcode:2004A&A...415..609S. doi:10.1051/0004-6361:20034623. S2CID   3000175.
  9. ↑ Schaefer, Bradley E. (2009). "Orbital Periods for Three Recurrent Novae". The Astrophysical Journal. 697 (1): 721–729. arXiv: 0903.1349 . Bibcode:2009ApJ...697..721S. doi:10.1088/0004-637X/697/1/721. S2CID   16087253.
  10. 1 2 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. Bibcode:2008PASP..120..492W. doi: 10.1086/587965 . S2CID   106406607.
  11. ↑ Andrews, Robin George (8 March 2024). "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 . Archived from the original on 8 March 2024. Retrieved 9 March 2024.
  12. ↑ Pettit, Edison (1946). "The Light-Curves of T Coronae Borealis". Publications of the Astronomical Society of the Pacific. 58 (341): 153. Bibcode:1946PASP...58..153P. doi: 10.1086/125797 .
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  15. ↑ Thompson, Joanna (September 15, 2023). "Evidence of mysterious 'recurring nova' that could reappear in 2024 found in medieval manuscript from 1217". Live Science. Retrieved 2024-03-21.
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  17. ↑ Schaefer, Bradley E. (2010). "Comprehensive Photometric Histories of All Known Galactic Recurrent Novae". The Astrophysical Journal Supplement Series. 187 (2): 275–373. arXiv: 0912.4426 . Bibcode:2010ApJS..187..275S. doi:10.1088/0067-0049/187/2/275. S2CID   119294221.
  18. ↑ "Vmag<2.5". SIMBAD Astronomical Database. Retrieved 2010-06-25.
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  20. ↑ 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. arXiv: 1607.06804 . Bibcode:2016MNRAS.462.2695I. doi:10.1093/mnras/stw1837. S2CID   119104759.
  21. ↑ Luna, GJM; Mukai, K.; Sokoloski, J. L.; Nelson, T.; Kuin, P.; Segreto, A.; Cusumano, G.; Jaque Arancibia, M.; Nuñez, N. E. (2018). "Dramatic change in the boundary layer in the symbiotic recurrent nova T Coronae Borealis". Astronomy and Astrophysics. 619 (1): 61. arXiv: 1807.01304 . Bibcode:2018A&A...619A..61L. doi:10.1051/0004-6361/201833747. S2CID   119078482.
  22. ↑ "Is T CrB About to Blow its Top?". Sky & Telescope website. 20 April 2016. Retrieved 2017-08-06.
  23. ↑ Schaefer, B.E.; Kloppenborg, B.; Waagen, E.O. "Announcing T CrB pre-eruption dip". AAVSO. American Association of Variable Star Observers. Retrieved 18 January 2024.
  24. ↑ Todd, Ian. "T Coronae Borealis nova event guide and how to prepare". Sky at Night Magazine. BBC. Retrieved 18 March 2024.

Further reading