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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 606337.0, MPI für Astronomie / Publikationen_mpia
The nearby eclipsing stellar system s Velorum. III. Self-consistent fundamental parameters and distance
Authors:Mérand, A.; Kervella, P.; Pribulla, T.; Petr-Gotzens, M. G.; Benisty, M.; Natta, A.; Duvert, G.; Schertl, D.; Vannier, M.
Date of Publication (YYYY-MM-DD):2011
Journal Abbrev.:Astronomy and Astrophysics
Start Page:50
Audience:Not Specified
Abstract / Description:Context. The triple stellar system δ Vel (composed of two A-type and one F-type main-sequence stars) is particularly interesting because it contains one of the nearest and brightest eclipsing binaries. It therefore presents a unique opportunity to determine independently the physical properties of the three components of the system, as well as its distance. <BR /> Aims: We aim at determining the fundamental parameters (masses, radii, luminosities, rotational velocities) of the three components of δ Vel, as well as the parallax of the system, independently from the existing Hipparcos measurement. <BR /> Methods: We determined dynamical masses from high-precision astrometry of the orbits of Aab-B and Aa-Ab using adaptive optics (VLT/NACO) and optical interferometry (VLTI/AMBER). The main component is an eclipsing binary composed of two early A-type stars in rapid rotation. We modeled the photometric and radial velocity measurements of the eclipsing pair Aa-Ab using a self-consistent method based on physical parameters (mass, radius, luminosity, rotational velocity). <BR /> Results: From our self-consistent modeling of the primary and secondary components of the δ Vel A eclipsing pair, we derive their fundamental parameters with a typical accuracy of 1%. We find that they have similar masses, 2.43 ± 0.02 M&sun; and 2.27 ± 0.02 M&sun;. The physical parameters of the tertiary component (δ Vel B) are also estimated, although to a lower accuracy. We obtain a parallax Ï€ = 39.8 ± 0.4 mas for the system, in satisfactory agreement (-1.2 σ) with the Hipparcos value (Ï€Hip = 40.5 ± 0.4 mas). <BR /> Conclusions: The physical parameters we derive represent a consistent set of constraints for the evolutionary modeling of this system. The agreement of the parallax we measure with the Hipparcos value to a 1% accuracy is also an interesting confirmation of the true accuracy of these two independent measurements. Based on observations made with ESO telescopes at Paranal Observatory, under ESO programs 076.D-0782(B), 081.D-0109(B), 081.D-0109(C), 282.D-5006(A) and Arcetri GTO program 084.C-0170(C).
Free Keywords:binaries: eclipsing; stars: early-type; stars: rotation; stars: individual:δVelorum (HD 74956); techniques: high angular resolution; techniques: interferometric
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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