Detalles de publicación

PP 018067

Testing tidal theory for evolved stars by using red-giant binaries observed by Kepler

P. G. Beck(1,2), S. Mathis(3,4,5), F. Gallet(6), C. Charbonnel(6,7), M. Benbakoura(3), R. A. García(3), J.-D. do Nascimento Jr (8,9)
1 Instituto de Astrofısica de Canarias, E-38200 La Laguna, Tenerife, Spain 2 Departamento de Astrof´ısica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain 3 IRFU, CEA, Universit´e Paris-Saclay, F-91191 Gif-sur-Yvette, France 4 Universit´e Paris Diderot, AIM, Sorbonne Paris Cit´e, CEA, CNRS, F-91191 Gif-sur-Yvette, France 5 LESIA, Observatoire de Paris, PSL Research Univ., CNRS, Univ. Pierre et Marie Curie, Univ. Paris Diderot, 92195 Meudon, France 6 Department of Astronomy, University of Geneva, Chemin des Maillettes 51, 1290, Versoix, Switzerland 7 IRAP, UMR 5277, CNRS and Universit´e de Toulouse, 14 Av. E. Belin, 31400, Toulouse, France 8 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA 9 Departamento de Fısica, Universidade Federal do Rio Grande do Norte, CEP: 59072-970 Natal, RN, Brazil
Tidal interaction governs the redistribution of angular momentum in close binary stars and planetary systems and determines the systems evolution towards the possible equilibrium state. Turbulent friction acting on the equilibrium tide in the convective envelope of low-mass stars is known to have a strong impact on this exchange of angular momentum in binaries. Moreover, theoretical modelling in recent literature as well as presented in this paper suggests that the dissipation of the dynamical tide, constituted of tidal inertial waves propagating in the convective envelope, is weak compared to the dissipation of the equilibrium tide during the red-giant phase. This prediction is confirmed when we apply the equilibrium-tide formalism developed by Zahn (1977), Verbunt & Phinney (1995), and Remus, Mathis & Zahn (2012) onto the sample of all known red-giant binaries observed by the NASA Kepler mission. Moreover, the observations are adequately explained by only invoking the equilibrium tide dissipation. Such ensemble analysis also benefits from the seismic characterisation of the oscillating components and surface rotation rates. Through asteroseismology, previous claims of the eccentricity as an evolutionary state diagnostic are discarded. This result is important for our understanding of the evolution of multiple star and planetary systems during advanced stages of stellar evolution.

 
Aceptado para publicación en MNRAS Letters | Enviado el 2018-06-20 | Proyecto P/300008