Abstract

Sparse Aperture Masking of Massive Stars

Hugues Sana (Amsterdam University)

H. Sana, S. Lacours, J.-B. Le Bouquin, A. de Koter, C. Moni-Bidin, L. Muijres, O. Schnurr, H. Zinnecker

The Sparse Aperture Masking (SAM) mode of NACO/VLT provides a unique opportunity to explore the immediate surroundings of massive stars. Equipped on a 8-m class telescope, the simultaneous combination of short baseline interferometry and AO-corrected imaging up to 6 arcsec from the source makes it one of the most sensitive and efficient facilities for this purpose, allowing for a survey approach.

We present the earliest results of our campaign on a sample of 60 O-type stars. In particular, we detected ∆Ks < 5 mag companions for 20-25% of our targets with separations in the range 30-100 mas (typically, 40 − 200 A.U.). Most of these companions were unknown, shedding thus new light on the multiplicity properties of the massive stars in a separation regime that has been difficult to explore so far. Including companion detections from other techniques (including spectroscopy, interferometry, speckle, AO), the multiplicity fraction of our sample is larger than 80%, which the largest multiplicity fraction ever found. We briefly discuss our sensitivity limit and the impact of detection biases on our results.

Mode of presentation: poster