Letter to the Editor
δ Centauri: a new binary Be star detected by VLTI/AMBER spectro-interferometry*
Max Planck Intitut fur Radioastronomie, Auf dem Hugel 69, 53121 Bonn, Germany e-mail: firstname.lastname@example.org
2 Laboratoire A.H. FIZEAU, UMR 6525, UNS/OCA/CNRS, Campus Valrose, 06108 Nice Cedex 2, France
3 Laboratoire d'Astrophysique de Grenoble, UMR 5571 Université Joseph Fourier/CNRS, BP 53, 38041 Grenoble Cedex 9, France
4 INAF – Osservatorio Astrofisico di Arcetri, Istituto Nazionale di Astrofisica, Largo E. Fermi 5, 50125 Firenze, Italy
Accepted: 29 July 2008
Aims. We study the Be star δ Cen circumstellar disk using long-baseline interferometry which is the only observing technique capable of resolving spatially and spectroscopically objects smaller than 5 mas in the H and K band.
Methods. We used the VLTI/AMBER instrument on January 6, 8, and 9, 2008, in the H and K bands to complete low (35) and medium (1500) spectral resolution observations.
Results. We detected an oscillation in the visibility curve plotted as a function of the spatial frequency which is a clear signature of a companion around δ Cen. Our best-fit soltution infers a binary separation of 68.7 mas, a companion flux contribution in the K band of about 7% of the total flux, a PA of 117.5°, and an envelope flux around the Be primary that contributes up to about 50% of the total flux, in agreement with our Spectral Energy Distribution (SED) fit. The envelope size is estimated to be 1.6 mas in K but no departure from spherical symmetry is detected.
Key words: techniques: high angular resolution / techniques: interferometric / stars: emission-line, Be / stars: binaries: close / stars: winds, outflows / stars: circumstellar matter
© ESO, 2008