J/AJ/148/37 Long-term photometric behavior of V404 Lyr (Lee+, 2014)
The eclipsing system V404 Lyr: light-travel times and γ Doradus
pulsations.
Lee J.W., Kim S.-L., Hong K., Lee C.-U., Koo J.-R.
<Astron. J., 148, 37 (2014)>
=2014AJ....148...37L 2014AJ....148...37L
ADC_Keywords: Binaries, eclipsing
Keywords: binaries: close - binaries: eclipsing - stars: individual: V404 Lyr -
stars: oscillations - starspots
Abstract:
We present the physical properties of V404 Lyr exhibiting eclipse
timing variations and multiperiodic pulsations from all historical
data including the Kepler and SuperWASP observations. Detailed
analyses of 2922 minimum epochs showed that the orbital period has
varied through a combination of an upward-opening parabola and two
sinusoidal variations, with periods of P3=649days and P4=2154days
and semi-amplitudes of K3=193s and K4=49s, respectively. The
secular period increase at a rate of +1.41x10-7days/yr could be
interpreted as a combination of the secondary to primary mass transfer
and angular momentum loss. The most reasonable explanation for both
sinusoids is a pair of light-travel-time effects due to two
circumbinary objects with projected masses of M3=0.47M☉ and
M4=0.047M☉. The third-body parameters are consistent with
those calculated using the Wilson-Devinney binary code. For the
orbital inclinations i4≳43°, the fourth component has a mass
within the hydrogen-burning limit of ∼0.07M☉, which implies that
it is a brown dwarf. A satisfactory model for the Kepler light curves
was obtained by applying a cool spot to the secondary component. The
results demonstrate that the close eclipsing pair is in a
semi-detached, but near-contact, configuration; the primary fills
approximately 93% of its limiting lobe and is larger than the
lobe-filling secondary. Multiple frequency analyses were applied to
the light residuals after subtracting the synthetic eclipsing curve
from the Kepler data. This revealed that the primary component of V404
Lyr is a γ Dor type pulsating star, exhibiting seven pulsation
frequencies in the range of 1.85-2.11/day with amplitudes of
1.38-5.72mmag and pulsation constants of 0.24-0.27days. The seven
frequencies were clearly identified as high-order low-degree
gravity-mode oscillations which might be excited through tidal
interaction. Only eight eclipsing binaries have been known to contain
γ Dor pulsating components and, therefore, V404 Lyr will be an
important test bed for investigating these rare and interesting
objects.
Description:
From the Kepler observations of V404 Lyr, we determined 2882 eclipse
timings and their errors using the method presented by Kwee & van
Woerden (1956BAN....12..327K 1956BAN....12..327K). 12 additional eclipses were obtained
using the data from the SuperWASP (Wide Angle Search for Planets)
public archive (Butters et al., 2010A&A...520L..10B 2010A&A...520L..10B).
Objects:
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RA (ICRS) DE Designation(s) (Period)
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19 19 05.94 +38 22 00.5 V404 Lyr = KIC 3228863 (P=0.73094)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 49 2894 SuperWASP (Wide Angle Search for Planets) and
Kepler eclipse timings for V404 Lyr
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
J/AJ/147/45 : Kepler mission. IV. Eclipse times for close binaries
(Conroy+, 2014)
J/AJ/142/160 : Kepler Mission. II. 2165 eclipsing binaries (Slawson+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 d BJD Barycentric Julian Date (1)
15- 21 F7.5 d e_BJD Error in BJD (1)
23- 28 F6.1 --- Epoch [-989/1966] Epoch (cycle) number
30- 37 F8.5 d O-C1 Residual from Equation (1) ephemeris (2)
39- 46 F8.5 d O-C2 Residual from Equation (2) ephemeris (3)
48- 49 A2 --- Type Minimum type: I (integer epoch) or II
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Note (1): From the Kepler observations of V404 Lyr, we determined 2882 eclipse
timings and their errors using the method presented by Kwee & van Woerden
(1956BAN....12..327K 1956BAN....12..327K). 12 additional eclipses were obtained using the data
from the SuperWASP (Wide Angle Search for Planets) public archive
(Butters et al., 2010A&A...520L..10B 2010A&A...520L..10B)
Note (2): C1=T0+PE+τ3, where T0 is the ephemeris epoch, and τ3
is the Light-Travel Time (LTT) due to a tertiary companion (Irwin) and
includes five parameters a12sini3, e, ω, n, Tperi). Here,
a12sini3, e, and ω are the orbital parameters of the eclipsing
pair around the mass center of the triple system. The parameters n and
Tperi denote the Keplerian mean motion of the mass center of the binary
components and its epoch of periastron passage, respectively.
Note (3): C2=T0+PE+AE2+τ3+τ4.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 15-Oct-2014