J/AJ/157/150 Mid-eclipse times of KIC 10544976 (Almeida+, 2019)
Orbital period variation of KIC 10544976: Applegate mechanism versus light
travel time effect.
Almeida L.A., de Almeida L., Damineli A., Rodrigues C.V., Castro M.,
Lopes C.E.F., Jablonski F., do Nascimento J.-D., Pereira M.G.
<Astron. J., 157, 150 (2019)>
=2019AJ....157..150A 2019AJ....157..150A (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Stars, white dwarf
Keywords: binaries: eclipsing - planetary systems - stars: activity -
stars: flare - stars: individual (KIC 10544976) - starspots
Abstract:
In recent years, several close post-common-envelope eclipsing binaries
have been found to show cyclic eclipse timing variations (ETVs). This
effect is usually interpreted either as the gravitational interaction
among circumbinary bodies and the host binary - known as the light travel
time (LTT) effect - or as the quadrupole moment variations in one magnetic
active component - known as the Applegate mechanism. In this study, we
present an analysis of the ETV and the magnetic cycle of the close binary
KIC 10544976. This system is composed of a white dwarf and a red dwarf
in a short orbital period (0.35 days) and was monitored by ground-based
telescopes between 2005 and 2017 and by the Kepler satellite between
2009 and 2013. Using the Kepler data, we derived the magnetic cycle of
the red dwarf by two ways: the rate and energy of flares and the
variability due to spots. Both methods resulted in a cycle of ∼600 days,
which is in agreement with magnetic cycles measured for single low-mass
stars. The orbital period of KIC 10544976 shows only one long-term
variation which can be fitted by an LTT effect with period of ∼16.8 yr.
Hence, one possible explanation for the ETVs is the presence of a
circumbinary body with a minimal mass of ∼13.4 MJup. In the particular
scenario of coplanarity between the external body and the inner binary,
the third body mass is also ∼13.4 MJup. In this case, the circumbinary
planet must either have survived the evolution of the host binary or
have been formed as a consequence of its evolution.
Description:
The KIC 10544976 data were retrieved from the Kepler data search
webpages (http://exoplanetarchive.ipac.caltech.edu;
http://archive.stsci.edu/pub/kepler/ffi). We use the Presearch Data
Conditioning (http://keplergo.arc.nasa.gov/PipelinePDC.shtml) (PDC)
and the full frame images (FFIs). Raw photometric data of KIC 10544976
and calibration (flat-field and bias) images were retrieved from the
Isaac Newton Group public archive
(http://casu.ast.cam.ac.uk/casuadc/ingarch/query). The photometric
observations were performed with the Auxiliary-port CAMera attached to
the 4.2 m William Herschel Telescope (WHT) and with the Wide Field
Camera coupled to the 2.54 m INT at Roque de los Muchachos Observatory.
The observations were done on 2008 August 28 and 2014 July 21 (WHT),
and on 2017 April 5 (INT).
We use the same approach described in Almeida et al. (2013ApJ...766...11A 2013ApJ...766...11A)
to derive the mid-eclipse times and their uncertainties. In short, a Markov
chain Monte Carlo (MCMC) procedure was performed to sample the mid-eclipse
time and to examine the marginal posterior distribution of the probability
of the parameters. The median of the distribution provides the mid-eclipse
time and the area corresponding to the 1σ percentile provides the
uncertainty. Our 2745 new mid-eclipse times from the Kepler, WHT, and
INT data, and previous values obtained by Almenara et al.
(2012MNRAS.420.3017A 2012MNRAS.420.3017A) are presented in Table 1.
Objects:
--------------------------------------------------------------------
RA (ICRS) DE Designation(s)
--------------------------------------------------------------------
19 42 37.19 +47 45 48.4 KIC 10544976 = 2MASS J19423720+4745486
--------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 65 2755 Mid-eclipse times of KIC 10544976
--------------------------------------------------------------------------------
See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/AJ/147/45 : Kepler mission. IV. Eclipse times for close binaries
(Conroy+, 2014)
J/AJ/151/68 : Kepler Mission. VII. Eclipsing binaries in DR3 (Kirk+, 2016)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- Cycle [1/12154] Cycle count from T0
7- 16 F10.5 d Time [3590.43688/7849.68592] Mid-eclipse time
(BJD-2450000)
18- 24 F7.5 d e_Time [1e-05/0.00252] 1σ uncertainty in Time
26- 45 A20 --- Ref Reference
47- 65 A19 --- Bibcode Bibcode of the reference
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 11-Jul-2019