Dynamical masses, absolute radii and 3D orbits of the triply eclipsing star HD 181068 from Kepler photometry

Borkovits, T. and Derekas, A. and Kiss, L. L. and Király, A. and Forgácsné Dajka, E. and Biro, I. B. and Bedding, T. R. and Bryson, S. T. and Huber, D. and Szabó, Róbert (2013) Dynamical masses, absolute radii and 3D orbits of the triply eclipsing star HD 181068 from Kepler photometry. Monthly Notices of the Royal Astronomical Society. ISSN 0035-8711


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HD 181068 is the brighter of the two known triply eclipsing hierarchical triple stars in the Kepler field. It has been continuously observed for more than 2 yr with the Kepler space telescope. Of the nine quarters of the data, three have been obtained in short-cadence mode, that is one point per 58.9 s. Here we analyse this unique data set to determine absolute physical parameters (most importantly the masses and radii) and full orbital configuration using a sophisticated novel approach. We measure eclipse timing variations (ETVs), which are then combined with the single-lined radial velocity measurements to yield masses in a manner equivalent to double-lined spectroscopic binaries. We have also developed a new light-curve synthesis code that is used to model the triple, mutual eclipses and the effects of the changing tidal field on the stellar surface and the relativistic Doppler beaming. By combining the stellar masses from the ETV study with the simultaneous light-curve analysis we determine the absolute radii of the three stars. Our results indicate that the close and the wide subsystems revolve in almost exactly coplanar and prograde orbits. The newly determined parameters draw a consistent picture of the system with such details that have been beyond reach before.

Item Type: Article
Subjects: Q Science / természettudomány > QB Astronomy, Astrophysics / csillagászat, asztrofizika
Depositing User: Dr. Aliz Derekas
Date Deposited: 28 Sep 2015 13:29
Last Modified: 28 Sep 2015 14:38

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