Interferometry, spectroscopy and astrometry of the bright eclipsing system Delta Velorum

TL;DR

This study combines spectroscopy, astrometry, and interferometry to precisely determine the physical and orbital parameters of the bright eclipsing system Delta Velorum, including its masses, radii, and parallax.

Contribution

It provides a comprehensive, multi-technique analysis of Delta Velorum, deriving fundamental stellar parameters with high accuracy and confirming system distance with Hipparcos data.

Findings

Eclipsing stars have similar masses (~2.4 and 2.3 Msun).

Derived parallax (39.8 mas) agrees with Hipparcos measurement.

Achieved 1% accuracy in fundamental stellar parameters.

Abstract

The bright southern star Delta Vel is a multiple system comprising at least three stars. Its brightest component, Delta Vel A, was identified in 2000 as one of the brightest eclipsing system in the sky. Its eclipses are easily observable with the unaided eye, a remarkable property shared only by Algol, Beta Aur, Alpha CrB and Psi Cen. We determined dynamical masses from a combination of spectroscopy, high-precision astrometry of the orbits of Aab-B and Aa-Ab using adaptive optics (VLT/NACO) and optical interferometry (VLTI/AMBER). The main eclipsing component is a pair of 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). From this modeling, we derive the fundamental parameters of the eclipsing stars with a typical accuracy of 1%. We find that they have similar masses, respectively 2.43 +/- 0.02 and 2.27 +/- 0.02 Msun. The physical parameters of the tertiary component (Delta Vel B) are also derived, although to a lower accuracy, as well as the parallax of the system, 39.8 +/- 0.4 mas. This value is in satisfactory agreement (-1.2 sigma) with the Hipparcos parallax of the system (pi_Hip =40.5 +/- 0.4 mas).