binaries: eclipsing; stars: early-type; stars: formation; stars: individual: CV Velorum DI Herculis EP Crucis; stars: kinematics and dynamics; stars: rotation; techniques: spectroscopic
Abstract :
[en] As part of the Binaries Are Not Always Neatly Aligned project (BANANA), we have found that the eclipsing binary CV Velorum has misaligned rotation axes. Based on our analysis of the Rossiter-McLaughlin effect, we find sky-projected spin-orbit angles of β[SUB]p[/SUB] = -52° ± 6° and β[SUB]s[/SUB] = 3° ± 7° for the primary and secondary stars (B2.5V + B2.5V, P = 6.9 days). We combine this information with several measurements of changing projected stellar rotation speeds (vsin i [SUB]sstarf[/SUB]) over the last 30 yr, leading to a model in which the primary star's obliquity is ≈65°, and its spin axis precesses around the total angular momentum vector with a period of about 140 yr. The geometry of the secondary star is less clear, although a significant obliquity is also implicated by the observed time variations in the vsin i [SUB]sstarf[/SUB]. By integrating the secular tidal evolution equations backward in time, we find that the system could have evolved from a state of even stronger misalignment similar to DI Herculis, a younger but otherwise comparable binary. Based on observations made with ESOs 2.2 m Telescopes at the La Silla Paranal Observatory under programme ID 084.C-1008 and under MPIA guaranteed time.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Albrecht, Simon; Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Winn, Joshua N.; Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Torres, Guillermo; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA
Fabrycky, Daniel C.; Department of Astronomy and Astrophysics, University of California Santa Cruz, Santa Cruz, CA 95064, USA
Setiawan, Johny; Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany ; Embassy of the Republic of Indonesia, Lehrter Str. 16-17, D-10557 Berlin, Germany
Gillon, Michaël ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa)
Jehin, Emmanuel ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa)
Triaud, Amaury; Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA ; Observatoire Astronomique de lÚniversité de Genève, Chemin des Maillettes 51, Sauverny CH-1290, Switzerland ; Fellow of the Swiss national science foundation.
Queloz, Didier; Observatoire Astronomique de lÚniversité de Genève, Chemin des Maillettes 51, Sauverny CH-1290, Switzerland ; Astrophysics Group, Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, UK
Snellen, Ignas; Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
Eggleton, Peter; Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94551, USA)
Language :
English
Title :
The BANANA Project. V. Misaligned and Precessing Stellar Rotation Axes in CV Velorum
Publication date :
01 April 2014
Journal title :
Astrophysical Journal
ISSN :
0004-637X
eISSN :
1538-4357
Publisher :
University of Chicago Press, United States - Illinois
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