J/AJ/157/111 Study of three early-type contact twin binaries (Yang+, 2019)
A comprehensive study of three early-type contact twin binaries: CT Tau, GU Mon,
and V701 Sco.
Yang Y., Yuan H., Dai H.
<Astron. J., 157, 111 (2019)>
=2019AJ....157..111Y 2019AJ....157..111Y (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Stars, early-type ; Spectra, optical ;
Spectra, infrared
Keywords: binaries: close - binaries: eclipsing - stars: early-type -
stars: individual (CT Tau, GU Mon, and V701 Sco)
Abstract:
Three eclipsing binaries, CT Tau, GU Mon, and V701 Sco, are early-type
contact binaries with infrared excess from circumbinary matter. We present
the multi-color photometry for CT Tau and GU Mon, whose spectral types
of B1V are identified by the low-precision spectra. Combining these new
light curves (LCs) with previously reported LCs and radial velocity curves,
we perform a synthesized analysis to estimate/update the stellar absolute
parameters of the three systems. Their mass ratios are close to unity
(i.e., q∼1), which indicates that the binary system comprising of twin
components may be undergoing a slow Case A mass transfer. From the period
analysis, the light-time orbit in the (O-C) curve may result from the third
condense companion around the binary system although no evidence could be
provided by the third light l3. From the spectral energy distribution
for three binaries, the excess infrared (IR) emissions are above the
photospheric emissions, which can be seen at the 22.1 µm for CT Tau
and GU Mon, and 11.6 µm, 14.5 µm, and 22.1 µm for V701 Sco,
respectively. This kind of infrared excess for the early-type star may
be attributed to the circumbinary matter by stellar wind.
Description:
Multi-color photometry for CT Tau and GU Mon was performed using the
85 cm telescope in 2010 December and the 60 cm telescope in 2016 January
and February at the Xinglong station (XLs) of National Astronomical
Observatories of China (NAOC). In the observing process, the standard
Johnson BVRc filters are mounted on two telescopes. The
low-resolution spectrograms for CT Tau and GU Mon were taken in 2017
using the 2.4 m telescope at the Lijiang station (LJs) of Yunan
Astronomical Observatories (YNAO), and the 2.16 m telescope at the XLs
of NAOC, respectively. During the observing process, we chose the Grism-14
with a wavelength coverage from 3200 to 7500 Å for the 2.4 m
telescope (Fan et al. 2016PASP..128k5005F 2016PASP..128k5005F), and the "E9+G10" with a
dispersion of 0.38-0.86 Å/pix and wavelength range of 3300-6400 Å
(Fan et al. 2015RAA....15..918F 2015RAA....15..918F). For two EBs, the exposure time of
10 minutes and the slit width of 1.8" are adopted.
Objects:
----------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------
05 58 50.11 +27 04 41.9 CT Tau = V* CT Tau
06 44 46.86 +00 13 18.3 GU Mon = V* GU Mon
17 34 24.51 -32 30 16.0 V701 Sco = V* V701 Sco
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 61 338 All available light minimum times for three
eclipsing binaries
table6.dat 103 65 Measured fluxes for the three eclipsing binaries
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See also:
V/120 : Catalog of early-type contact binaries (Bondarenko+, 1996)
J/A+A/426/1001 : Catalog of contact binary stars (Csizmadia+, 2004)
J/A+A/590/A45 : GU Mon BV light curves (Lorenzo+, 2016)
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Star Stellar identifier
10- 21 F12.4 d HJD [2427688.268/2458082.4029] Heliocentric Julian
Date
23- 28 F6.4 d e_HJD [0.0001/0.042]? Uncertainty in HJD
30- 32 A3 --- Meth Detection method (1)
34- 41 F8.1 --- Epoch [-28450/15789.5] Epoch number
43- 43 A1 --- Type [I] Eclipse type
45- 51 F7.4 d (O-C)i [-0.1566/0.0992] Initial residuals (2)
53- 59 F7.4 d (O-C)f [-0.1672/0.0431]? Final residuals
61 A1 --- f_(O-C)f [d] Indicates the (O-C)f is discarded
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Note (1): Detection method as follows:
p = Plate;
pe = Photoelectric;
pg = Photographic;
vi = Visual;
CCD = Charge-Coupled Device.
Note (2): Computed by using Kreiner et al. (2001aocd.book.....K 2001aocd.book.....K)'s ephemeris.
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Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Star Stellar identifier
10- 15 F6.3 um lambda [0.353/22.1] Wavelength λ
17- 23 F7.3 10-2Jy Flux [0.184/149] Flux density
25- 29 F5.3 10-2Jy e_Flux [0.014/5.1]? Uncertainty in Flux
30 A1 --- n_Flux [a] Note on Flux (1)
32- 47 A16 --- Band Band
49- 71 A23 --- Ref Reference
73- 91 A19 --- Bibcode Bibcode of the reference
93-103 A11 --- Cat Catalog reference in VizieR
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Note (1): Note as follows:
a = Assumed errors of 50% for measured fluxes in the W4 band due to absence
of its uncertainty.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 05-Jun-2019