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HD 181068: A Red Giant in a Triply Eclipsing Compact Hierarchical Triple System

2011; American Association for the Advancement of Science; Volume: 332; Issue: 6026 Linguagem: Inglês

10.1126/science.1201762

1095-9203

A. Derekas, L. L. Kiss, T. Borkovits, Daniel Huber, H. Lehmann, J. Southworth, T. R. Bedding, D. D. Balam, M. Hartmann, M. Hrudková, Michael Ireland, J. Kovács, György Mező, A. Moór, E. Niemczura, Gordon E. Sarty, Gy. M. Szabó, R. Szabó, J. H. Telting, A. Tkachenko, K. Uytterhoeven, J. M. Benkő, Stephen T. Bryson, Vicente Maestro, A. E. Simon, Dennis Stello, Gail Schaefer, C. Aerts, Theo A. ten Brummelaar, P. De Cat, Harold A. McAlister, C. Maceroni, A. Mérand, M. Still, J. Sturmann, L. Sturmann, N. Turner, Peter Tuthill, J. Christensen‐Dalsgaard, Ronald L. Gilliland, H. Kjeldsen, Elisa V. Quintana, Peter Tenenbaum, Joseph D. Twicken,

Astronomy and Astrophysical Research

Hierarchical triple systems comprise a close binary and a more distant component. They are important for testing theories of star formation and of stellar evolution in the presence of nearby companions. We obtained 218 days of Kepler photometry of HD 181068 (magnitude of 7.1), supplemented by groundbased spectroscopy and interferometry, which show it to be a hierarchical triple with two types of mutual eclipses. The primary is a red giant that is in a 45-day orbit with a pair of red dwarfs in a close 0.9-day orbit. The red giant shows evidence for tidally-induced oscillations that are driven by the orbital motion of the close pair. HD 181068 is an ideal target for studies of dynamical evolution and testing tidal friction theories in hierarchical triple systems.