J/A+A/636/A77 V426 Sagittae (HBHA 1704-05) light curves (Skopal+, 2020)
The path to Z And-type outbursts: The case of V426 Sagittae (HBHA 1704-05).
Skopal A., Shugarov S.Yu., Munari U., Masetti N., Marchesini E.,
Komzik R.M., Kundra E., Shagatova N., Tarasova T.N., Buil C., Boussin C.,
Shenavrin V.I., Hambsch F.-J., Dallaporta S., Frigo A., Garde O.,
Zubareva A., Dubovsky P.A., Kroll P.
<Astron. Astrophys. 636, A77 (2020)>
=2020A&A...636A..77S 2020A&A...636A..77S (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, cataclysmic ; Photometry, UBVRI ;
Photometry, photographic
Keywords: binaries: symbiotic - novae - cataclysmic variables -
stars: individual: V426 Sagittae (HBHA 1704-05)
Abstract:
The star V426 Sge (HBHA 1704-05), originally classified as an
emission-line object and a semi-regular variable, brightened at the
beginning of August 2018, showing signatures of a symbiotic star
outburst. We aim to confirm the nature of V426 Sge as a classical
symbiotic star, determine the photometric ephemeris of the light
minima, and suggest the path from its 1968 symbiotic nova outburst to
the following 2018 Z And-type outburst. We re-constructed an
historical light curve (LC) of V426 Sge from approximately the year
1900, and used original low- (R∼500-1500; 330-880nm) and
high-resolution (R∼11000-34000; 360-760nm) spectroscopy complemented
with Swift-XRT and UVOT, optical UBVRCIC and near-infrared $JHKL$
photometry obtained during the 2018 outburst and the following
quiescence. The historical LC reveals no symbiotic-like activity from
∼1900 to 1967. In 1968, V426 Sge experienced a symbiotic nova outburst
that ceased around 1990. From approximately 1972, a wave-like
orbitally related variation with a period of 493.4±0.7-days
developed in the LC. This was interrupted by a Z And-type outburst
from the beginning of August 2018 to the middle of February 2019. At
the maximum of the 2018 outburst, the burning white dwarf (WD)
increased its temperature to ≳2x105K, generated a luminosity of
∼7x1037(d/3.3kpc2erg/s, and blew a wind at the rate of
∼3x10-6M☉/yr. Our spectral energy distribution models from the
current quiescent phase reveal that the donor is a normal M4-5 III
giant characterised with Teff∼3400K, RG∼106(d/3.3kpc)R☉ and
LG∼1350(d/3.3kpc)2L☉ and the accretor is a low-mass
∼0.5M☉ WD. During the transition from the symbiotic nova
outburst to the quiescent phase, a pronounced sinusoidal variation
along the orbit develops in the LC of most symbiotic novae. The
following eventual outburst is of Z And-type, when the accretion by
the WD temporarily exceeds the upper limit of the stable burning. At
this point the system becomes a classical symbiotic star.
Description:
Multicolour photometry in the standard Johnson-Cousins UBVRcIc system,
and historical photographic photometry of the symbiotic star V426 Sge
is presented in Table A.1, A.2, and A.3, respectively.
Measurements were obtained at different observatories (G1, G2, KS), by
different telescopes (0310, 2100) and retrieved from the Moscow (M)
and Sonneberg (S) plate archives.
Objects:
--------------------------------------------------
RA (2000) DE Designation(s)
--------------------------------------------------
19 54 42.80 +17 22 14.6 V426 Sge = HBHA 1704-05
--------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 106 132 Observed U,B,V,Rc,Ic magnitudes
tablea2.dat 93 115 Observed B,V,Rc,Ic magnitudes
tablea3.dat 57 838 Photographic m_pg and m_pv magnitudes
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 10 F9.3 --- JD Julian date (UT), JD-2400000
13- 26 A14 "datime" Obs.date Observation date, YYYY/MM/DD.ddd
29- 34 F6.3 mag Umag ?=99 U magnitude
36- 41 F6.3 mag e_Umag ?=99 Error in U magnitude
44- 49 F6.3 mag Bmag ?=99 B magnitude
51- 56 F6.3 mag e_Bmag ?=99 Error in B magnitude
59- 64 F6.3 mag Vmag ?=99 V magnitude
67- 71 F5.3 mag e_Vmag ?=99 Error in V magnitude
74- 79 F6.3 mag Rcmag ?=99 Rc magnitude
81- 86 F6.3 mag e_Rcmag ?=99 Error in Rc magnitude
89- 94 F6.3 mag Icmag ?=99 Ic magnitude
96-101 F6.3 mag e_Icmag ?=99 Error in Ic magnitude
105-106 A2 --- Obs Observatory (1)
--------------------------------------------------------------------------------
Note (1): Observatory code as follows:
G1 = Stara Lesna Observatory, pavilion G1
G2 = Stara Lesna Observatory, pavilion G2
KS = Astronomical Observatory at the Kolonica Saddle
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 10 F9.3 --- JD Julian date (UT), JD-2400000
13- 26 A14 "datime" Obs.date Observation date, YYYY/MM/DD.ddd
29- 34 F6.3 mag Bmag ?=99 B magnitude
37- 41 F5.3 mag e_Bmag ?=99 Error in B magnitude
44- 49 F6.3 mag Vmag ?=99 V magnitude
52- 56 F5.3 mag e_Vmag ?=99 Error in V magnitude
59- 64 F6.3 mag Rcmag ?=99 Rc magnitude
66- 71 F6.3 mag e_Rcmag ?=99 Error in Rc magnitude
75- 79 F5.3 mag Icmag ?=99 Ic magnitude
82- 86 F5.3 mag e_Icmag ?=99 Error in Ic magnitude
90- 93 I4 --- Tel Telescope of the ANS collaboration
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 10 F9.3 --- JD Julian date (UT), JD-2400000
13- 26 A14 "datime" Obs.date Observation date, YYYY/MM/DD.ddd
29- 33 F5.2 mag pgmag ?=99 Photographic mpg magnitude
35- 39 F5.2 mag e_pgmag ?=99 Error in mpg magnitude
42- 46 F5.2 mag pvmag ?=99 Photographic mpv magnitude
48- 52 F5.2 mag e_pvmag ?=99 Error in mpv magnitude
56- 57 A2 --- Arch Plate archive (1)
--------------------------------------------------------------------------------
Note (1): Plate archive code as follows:
M = Moscow University archive
S = Sonneberg Observatory archive
MX = limiting magnitude on M plates with unseen target
--------------------------------------------------------------------------------
Acknowledgements:
Augustin Skopal, skopal(at)ta3.sk
(End) Patricia Vannier [CDS] 19-Mar-2020