delta Cen: a new binary Be star detected by VLTI-AMBER spectro-interferometryReportar como inadecuado

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1 MPIFR - Max Planck Institute Für RadioAstronomie 2 MPIFR - Max-Planck Institut für Radioastronomie 3 FIZEAU - Laboratoire Hippolyte Fizeau 4 LAOG - Laboratoire d-Astrophysique de Grenoble 5 OAA - INAF - Osservatorio Astrofisico di Arcetri

Abstract : 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.

Keywords : Stars: emission-line Stars: individual δ Cen Stars: circumstellar matter Stars: binary Techniques: high angular resolution Techniques: interferometric Be Stars: winds outflows

Autor: Anthony Meilland - Florentin Millour - Philippe Stee - Alain Spang - R. G. Petrov - D. Bonneau - Karine Perraut - Fabrizio Massi



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