• DOI:10.1051/0004-6361/202142418
• Corpus ID: 245353826

Probing the low-mass end of the companion mass function for O-type stars

@article{Reggiani2021ProbingTL,
  title={Probing the low-mass end of the companion mass function for O-type stars},
  author={Maddalena Reggiani and Alan Rainot and Hugues Sana and Leonardo A. Almeida and Saida M. Caballero-Nieves and Kaitlin M. Kratter and Sylvestre Lacour and Jean-Baptiste LeBouquin and Hans Zinnecker},
  journal={Astronomy \& Astrophysics},
  year={2021}
}

• M. Reggiani, A. Rainot, +6 authors H. Zinnecker
• Published 20 December 2021
• Physics
• Astronomy & Astrophysics

Context. Past observations of O-type stars in the Galaxy have shown that almost all massive stars are part of a binary or higher-order multiple system. Given the wide range of separations at which these companions are found, several observational techniques have been adopted to characterize them. Despite the recent advancements in interferometric and adaptive optics observations, contrasts greater than 4 in the H band have never been reached between 100 and 1000mas. Using new adaptive optics (AO) assisted coronagraphic observations, we aim to study the multiplicity properties of a sample of 18 dwarf (or sub-giant) O stars in the galactic field and in OB associations to probe the existence of stellar companions in the angular separation range from 0 . (cid:48)(cid:48) 15 to 6 (cid:48)(cid:48) down to very low mass ratios. 9 to 6 (cid:48)(cid:48) . Conclusions. These findings clearly support the notion that massive stars form almost exclusively in multiple systems, serving as proof of concept that supports the application of larger AO-assisted coronagraphic surveys as a crucial step in placing constraints on the multiplicity properties of massive star companions in regions of the parameter space that have previously gone unexplored. These results also demonstrate that the companion mass function is populated down to the lowest stellar masses.