J/A+A/701/A176 T CrB photometry and spectra (Munari+, 2025)
T CrB: Overview of the accretion history, Roche-lobe filling, orbital solution,
and radiative modeling.
Munari U., Walter F., Masetti N., Valisa P., Dallaporta S., Bergamini A.,
Cherini G., Frigo A., Maitan A., Marino C., Mazzacurati G., Moretti S.,
Tabacco F., Tomaselli S., Vagnozzi A., Ochner P., Albanese I.
<Astron. Astrophys. 701, A176 (2025)>
=2025A&A...701A.176M 2025A&A...701A.176M (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, cataclysmic ; Novae ; Photometry, UBVRI ;
Spectra, optical
Keywords: accretion, accretion disks - binaries: symbiotic -
novae, cataclysmic variables
Abstract:
Expectations for an imminent new outburst of the recurrent symbiotic
nova T CrB are mounting, initiated by the discovery in 2015 of a new
super-accretion phase (SAP), which is reminiscent of the one preceding
the last recorded outburst in 1946.
We aim to derive a robust estimate of the most important parameters
describing the physical nature of T CrB, trace the accretion history
onto its white dwarf, and account for the unexpected delay in the
occurrence of the new outburst: the SAP prior to 1946 was brighter,
and it was followed by the nova eruption within 6 months from its
conclusion. This time the 2015-2023 SAP has been fainter and two years
past its conclusion no new eruption has yet taken place.
Between 2005-2025, a period covering SAP and the preceding quiescence,
we collected a massive amount of photometric and spectroscopic
observations at optical wavelengths, that we have analyzed together
with the abundant ultraviolet observations available in the archive of
the Swift satellite.
Guided by the results of the orbital solution and in particular by the
radiative modeling to which we subjected the whole set of available
data, we found for T CrB a binary period of 227.556 days, an
inclination of 61 deg, and masses of 1.35 and 0.93 Msun for the white
dwarf and the M3III companion, respectively, making mass transfer
dynamically stable. The red giant fills completely its Roche lobe, and
at Vrot*sin(i)=4.75±0.26km/s it is rotating much slower that the 16
km/s co-rotation value. The 20deg azimuth of the hot spot, implied by
the hump shaping the optical light curve in quiescence, fixes the
outer radius of the disk to ∼58R☉, the same as the canonical
value expected from disk theory. In quiescence the disk is cold and
mostly neutral. SAP has been caused by an inside-out collapse of the
disk, during which the mean accretion rate onto the WD has been 28x
larger than in quiescence. SAP ended in late April 2023, but from May
2024 mass-flow has intensively resumed at disk inner radii while the
collapse wave reached the outer portions of the disk; the consequent
revamp in mass accretion could fill the gap inherited by the fainter
2015-2023 SAP and eventually lead the WD accreted shell to ignition.
Description:
CCD photometry of T CrB in the Landolt UBVRI bands is presented. The
data are fully transformed via color equations solved for each
observation from the local instantaneous photometric system to the
Landolt standard one. The quoted uncertainties are the total error
budget, which quadratically combine the Poisson error and the error
associated with the transformation to the standard system via the
color equations (usually the dominating term). The observations have
been acquired with various ANS Collaboration telescopes and with the
Asiago 67/92cm Schmidt camera, and cover from 2006 to 2025.
Set of spectra.
Objects:
-----------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------
15 59 30.16 +25 55 12.6 T CrB = HR 5958
-----------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 104 1383 UBVRI photometry of T CrB
spf2/* . 1 Spectrum of Fig. 2 (table A1)
spf34/* . 6 Individual spectra of Fig. 3 and 4 (table A1)
spf6/* . 4 Individual spectra of Fig. 6 (table A1)
spfb/* . 888 Individual spectra of Figs. B1, B2, B3, B4, B5
and B6 (table A1)
spfc/* . 63 Individual spectra of Fig. C1 (table A1)
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See also:
J/MNRAS/462/2695 : Symbiotic recurrent nova T CrB spectroscopy
(Ilkiewicz+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 "date" Date UT heliocentric observing date (YYYY/MM/DD.ddd)
16- 28 F13.5 --- HJD Heliocentric JD
30- 35 F6.3 mag Bmag ?=99.999 B band magnitude
37- 41 F5.3 mag e_Bmag ?=9.999 Error of B band magnitude
44- 49 F6.3 mag Vmag ?=99.999 V band magnitude
51- 55 F5.3 mag e_Vmag ?=9.999 Error of V band magnitude
58- 63 F6.3 mag Rmag ?=99.999 R band magnitude
65- 69 F5.3 mag e_Rmag ?=9.999 Error of R band magnitude
72- 77 F6.3 mag Imag ?=99.999 I band magnitude
79- 83 F5.3 mag e_Imag ?=9.999 Error of I band magnitude
86- 91 F6.3 mag Umag ?=99.999 U band magnitude
93- 97 F5.3 mag e_Umag ?=9.999 Error of U band magnitude
101-104 I4 --- Inst Telescope code
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Byte-by-byte Description of file (#): spf2/*
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Bytes Format Units Label Explanations
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3- 10 F8.3 0.1nm lambda Wavelength
15- 19 F5.3 10-16W/m2 Flux Flux (in 10-13erg/cm2/s)
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Byte-by-byte Description of file (#): spf34/*
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Bytes Format Units Label Explanations
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1- 16 F16.11 0.1nm lambda Wavelength
18- 30 E13.7 10mW/m2 Flux Flux (in erg/cm2/s/Å)
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Byte-by-byte Description of file (#): spf6/*
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Bytes Format Units Label Explanations
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3- 10 F8.3 0.1nm lambda Wavelength
13- 21 E9.4 10mW/m2 Flux Flux (in erg/cm2/s/Å)
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Byte-by-byte Description of file (#): spfb/*
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Bytes Format Units Label Explanations
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3- 10 F8.3 0.1nm lambda Wavelength
13- 18 F6.3 --- NFlux Normalized flux
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Byte-by-byte Description of file (#): spfc/*
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Bytes Format Units Label Explanations
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1- 7 F7.2 0.1nm lambda Wavelength
9- 24 E16.11 --- NFlux Normalized flux
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Acknowledgements:
Ulisse Munari, ulisse.munari(at)inaf.it
(End) Ulisse Munari [INAF, Padova], Patricia Vannier [CDS] 14-Aug-2025