@Article{AlmeidaADRCLJNP:2019:ApMeVe,
author = "Almeida, L. A. and Almeida, Leandro de and Damineli, A. and
Rodrigues, Cl{\'a}udia Vilega and Castro, M. and Lopes, C. E.
Ferreira and Jablonski, Francisco Jos{\'e} and Nascimento
J{\'u}nior, J. D. do and Pereira, M. G.",
affiliation = "{Universidade Federal do Rio Grande do Norte (UFRN)} and
{Universidade Federal do Rio Grande do Norte (UFRN)} and
{Universidade de S{\~a}o Paulo (USP)} and {Instituto Nacional de
Pesquisas Espaciais (INPE)} and {Universidade Federal do Rio
Grande do Norte (UFRN)} and {Universidade de S{\~a}o Paulo (USP)}
and {Instituto Nacional de Pesquisas Espaciais (INPE)} and
{Universidade Federal do Rio Grande do Norte (UFRN)} and
{Universidade Estadual de Feira de Santana}",
title = "Orbital period variation of KIC 10544976: applegate mechanism
versus light travel time effect",
journal = "Astronomical Journal",
year = "2019",
volume = "157",
number = "4",
pages = "e150",
month = "Apr.",
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 similar to 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
similar to 16.8 yr. Hence, one possible explanation for the ETVs
is the presence of a circumbinary body with a minimal mass of
similar to 13.4 M-Jup.In- the particular scenario of coplanarity
between the external body and the inner binary, the third body
mass is also similar to 13.4 M-Jup. 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.",
doi = "10.3847/1538-3881/ab0963",
url = "http://dx.doi.org/10.3847/1538-3881/ab0963",
issn = "0004-6256",
language = "en",
targetfile = "almeida_orbital.pdf",
urlaccessdate = "03 jun. 2024"
}