J/AJ/149/93 Eclipse timings of KIC 5621294 (Lee+, 2015)
The Kepler eclipsing system KIC 5621294 and its substellar companion.
Lee J.W., Hong K., Hinse T.C.
<Astron. J., 149, 93 (2015)>
=2015AJ....149...93L 2015AJ....149...93L
ADC_Keywords: Binaries, eclipsing
Keywords: binaries: close - binaries: eclipsing - brown dwarfs -
stars: individual: KIC 5621294 - stars: low-mass - starspots
Abstract:
We present the physical properties of KIC 5621294, showing light and
timing variations from the Kepler photometry. Its light curve displays
partial eclipses and the O'Connell effect, with Max II fainter than
Max I, which was fitted quite well by applying third-body and spot
effects to the system. The results indicate that the eclipsing pair is
a classical Algol-type system with parameters of q=0.22, i=76.8°,
and Δ(T1-T2)=4235K, in which the detached primary component
fills about 77% of its limiting lobe. Striking discrepancies exist
between the primary and secondary eclipse times obtained with the
method of Kwee & van Woerden. These are mainly caused by surface
inhomogeneities due to spot activity detected in our light curve
synthesis. The 1253 light curve timings from the Wilson-Devinney code
were used for a period study. It was found that the orbital period of
KIC 5621294 has varied due to periodic variation overlaid on a
downward parabola. The sinusoidal variation with a period of 961days
and a semi-amplitude of 22.5s most likely arises from a light-time
effect due to a third component with a mass of M3sini3=46.9MJup,
which is in good agreement with that calculated from the light curve
itself. If its orbital inclination is larger than about 40°, the
mass of the circumbinary object would possibly match a brown dwarf.
The parabolic variation could not be fully explained by either a mass
transfer between the binary components or angular momentum via
magnetic braking. It is possible that the parabola may be the only
observed part of a period modulation caused by the presence of another
companion in a wider orbit.
Description:
We determined 1804 times of minimum light and their errors from the
Kepler data using the method of Kwee & van Woerden (KW;
1956BAN....12..327K 1956BAN....12..327K). The 1253 timings determined by the
Wilson-Devinney code (W-D; Wilson & Devinney, 1971ApJ...166..605W 1971ApJ...166..605W; Van
Hamme & Wilson, 2007ApJ...661.1129V 2007ApJ...661.1129V) conformed to the general trend of
the primary minima obtained with the KW method, but are not matched
with the secondary ones at all.
Objects:
----------------------------------------------------------------------------
RA (ICRS) DE Designation(s) (Period)
----------------------------------------------------------------------------
19 28 52.63 +40 53 36.0 KIC 5621294 = 2MASS J19285262+4053359 (P=0.938905)
----------------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 40 1804 Minimum timings determined by the method of
Kwee & van Woerden (1956BAN....12..327K 1956BAN....12..327K)
table3.dat 35 1253 Minimum timings determined by the
Wilson-Devinney code (Wilson & Devinney,
1971ApJ...166..605W 1971ApJ...166..605W; Van Hamme & Wilson,
2007ApJ...661.1129V 2007ApJ...661.1129V)
--------------------------------------------------------------------------------
See also:
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
V/118 : Catalog of eclipsing binaries parameters (Perevozkina+, 1999)
J/AJ/148/37 : Long-term photometric behavior of V404 Lyr (Lee+, 2014)
J/AJ/147/91 : Differential BVR light curves of V407 Peg (Lee+, 2014)
J/AJ/147/45 : Kepler mission. IV. Timings for close binaries (Conroy+, 2014)
J/AJ/143/137 : Minima of eclipsing binaries from a Kepler survey (Gies+, 2012)
J/AJ/142/112 : KIC photometric calibration (Brown+, 2011)
J/AJ/139/2669 : CL Aur BVRI light curves (Lee+, 2010)
J/AJ/137/3181 : HW Vir differential VR light curves (Lee+, 2009)
J/A+A/450/681 : Companions to close spectroscopic binaries (Tokovinin+, 2006)
http://www.as.up.krakow.pl/o-c/ : Atlas of O-C diagrams of eclipsing binaries
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.5 d BJD Barycentric Julian Date
15- 21 F7.5 d e_BJD Uncertainty in BJD
23- 28 F6.1 --- Epoch [-765/799.5] Cycle number (.5 for type-II)
30- 37 F8.5 d O-C Observed minus Calculated timing (1)
39- 40 A2 --- Min Minimum type (I or II)
--------------------------------------------------------------------------------
Note (1): Computed with the linear ephemeris for the unspotted model in Table 1
of the paper.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.5 d BJD Barycentric Julian Date
15- 21 F7.5 d e_BJD Uncertainty in BJD
23- 26 I4 --- Epoch [-766/799] Cycle number
28- 35 F8.5 d O-C Observed minus Calculated timing (from the
complete ephemeris) (1)
--------------------------------------------------------------------------------
Note (1): The timings were finally fitted to a quadratic plus Light-Travel-Time
(LTT) ephemeris, as:
C=T0+PE+AE2+τ3 (Equation (1)), where τ3 is the LTT due to a
third body in the system (Irwin, 1952ApJ...116..211I 1952ApJ...116..211I, 1959AJ.....64..149I 1959AJ.....64..149I)
and includes five parameters (absini3, eb, ωb, nb, and
Tb). Here, absini3, eb, and ωb are the orbital parameters
of the close binary around the mass center of the triple system. The
parameters nb and Tb denote the Keplerian mean motion of the mass
center of the binary components and its epoch of periastron passage,
respectively.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 16-Mar-2015