Physical properties of the eclipsingδ Scuti star KIC 10661783

Abstract

Context. KIC 10661783 is an eclipsing binary that shows δ Scuti-like oscillations. More than 60 pulsation frequencies have been detected in its light curve as observed by the Kepler satellite. Aims. We want to determine the fundamental stellar and system parameters of the eclipsing binary as a precondition for asteroseismic modelling of the pulsating component and to establish whether the star is a semi-detached Algol-type system. Methods. We measured the radial velocities of both components from new high-resolution spectra using TODCOR and compute the orbit using PHOEBE. We used the KOREL program to decompose the observed spectra into its components, and analysed the decomposed spectra to determine the atmospheric parameters. For this, we developed a new computer program for the normalisation of the KOREL output spectra. Fundamental stellar parameters are determined by combining the spectroscopic results with those from the analysis of the Kepler light curve. Results. We obtain T eff , log g, v sin i, and the absolute masses and radii of the components, together with their flux ratio and separation. Whereas the secondary star rotates synchronously with the orbital motion, the primary star rotates subsynchronously by a factor of 0.75. The newly determined mass ratio of 0.0911 is higher than previously thought and means a detached configuration is required to fit the light curve. Conclusions. With its low orbital period and very low mass ratio, the system shows characteristics of the R CMa-type stars but differs from this group by being detached. Its current state is assumed to be that of a detached post-Algol binary system with a pulsating primary component.

Light Curve Solutions of 12 Eccentric Kepler Binaries and Analysis of Their Out-of-Eclipse Variability

“…The residual curves show greater scatters during the eclipse phases. Similar behavior could also be seen also for other Kepler binaries (Hambleton et al 2013, Lehmann et al 2013, Maceroni et al 2014, especially for those with small sum of relative radii. It has been attributed to the effects of finite integration time (Kipping 2010), but we found additional reasons for these discrepancies (see Section 3.1).…”

Light curve solutions of the eccentric Kepler binaries KIC 4281895 and KIC 5115178 with tidally-induced humps

“…1-10). Similar behavior could be seen also for other Kepler binaries (Hambleton et al 2013, Lehmann et al 2013, Maceroni et al 2014. We attributed them to the effects of finite integration time studied by Kipping (2010): (i) The large integration times smear out the light curve signal into a broader shape (see figure 1 of Kipping, 2010): the detected ingress and egress durations are bigger than their natural values (introducing an additional curvature into the eclipse wings) and the apparent positions of the contact points are temporally shifted from their true value; (ii) The large integration times smear out the curvature of the eclipse bottom caused by the limb-darkening effect.…”

Absolute Properties of the Pulsating Post-mass Transfer Eclipsing Binary OO Draconis

“…The physical properties of OO Dra are very similar to those of the pulsating EBs KIC 8262223 (Guo et al 2017) and KIC 10661783 (Lehmann et al 2013), which are detached binary stars with characteristics (low q, M 2 , and P combinations) of R CMa (Budding & Butland 2011) among Algols. At present, there have only been five R CMa-like binaries with accurate fundamental parameters from both time-series photometry and spectroscopy, including AS Eri (van Hamme & Wilson 1984;Ibanoǧlu et al 2006) and OGLEGC 228 (Kaluzny et al 2007).…”