# Spectro-interferometric observations of interacting massive stars with VEGA-CHARA - Astrophysics > Solar and Stellar Astrophysics

Abstract: We obtained spectro-interferometric observations in the visible of $\beta$Lyrae and $\upsilon$ Sgr using the instrument VEGA of the CHARA interferometricarray. For $\beta$ Lyrae, the dispersed fringe visibilities and differentialphases were obtained in spectral regions containing the H$\alpha$ and HeI 6678lines and the H$\beta$ and HeI 4921 lines. Whereas the source is unresolved inthe continuum, the source of the emission lines is resolved and the photocenterof the bulk of the H$\alpha$ emission exhibits offsets correlated with theorbital phase. For $\upsilon$ Sgr, both the continuum and H$\alpha$ sources areresolved, but no clear binary signal is detected. The differential phase shiftacross the line reveals that the bulk of the H$\alpha$ emission is clearlyoffset from the primary.

Author: Daniel Bonneau FIZEAU, Olivier Chesneau FIZEAU, Denis Mourard FIZEAU, Philippe Stee FIZEAU

Source: https://arxiv.org/