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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 710220.0, MPI für Astronomie / Publikationen_mpia
The BANANA project. V. Misaligned and precessing stellar rotation axes in CV Velorum
Authors:Albrecht, S.; Winn, J. N.; Torres, G.; Fabrycky, D. C.; Setiawan, J.; Gillon, M.; Jehin, E.; Triaud, A.; Queloz, D.; Snellen, I.; Eggleton, P.
Date of Publication (YYYY-MM-DD):2014
Title of Journal:The Astrophysical Journal
Issue / Number:2
Start Page:id. 83 (11 pp)
Audience:Not Specified
Abstract / Description: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 betap = -52° ± 6° and betas = 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 sstarf) 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 sstarf. 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.
Free Keywords:binaries: eclipsing; stars: early-type; stars: formation; stars: individual: CV Velorum DI Herculis EP Crucis; stars: kinematics and dynamics; stars: rotation; techniques: spectroscopic
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0004-637X %R 10.1088/0004-637X/785/2/83
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