Bibcode
Lorenzo, J.; Sanchez Bermudez, J.; Gamen, R. C.; Alonso-Santiago, J.; Marco, A.; Sota, A.; Simón-Díaz, S.; Walborn, N. R.; Pellerin, A.; Barbá, R. H.; Negueruela, I.; Maíz Apellániz, J.
Bibliographical reference
Astronomy and Astrophysics, Volume 579, id.A108, 12 pp.
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7
2015
Journal
Citations
21
Refereed citations
20
Description
Context. It appears that most (if not all) massive stars are born in
multiple systems. At the same time, the most massive binaries are hard
to find owing to their low numbers throughout the Galaxy and the implied
large distances and extinctions. Aims: We want to study LS III
+46 11, identified in this paper as a very massive binary; another
nearby massive system, LS III +46 12; and the surrounding stellar
cluster, Berkeley 90. Methods: Most of the data used in this
paper are multi-epoch high S/N optical spectra, although we also use
Lucky Imaging and archival photometry. The spectra are reduced with
dedicated pipelines and processed with our own software, such as a
spectroscopic-orbit code, CHORIZOS, and MGB. Results: LS III +46
11 is identified as a new very early O-type spectroscopic binary [O3.5
If* + O3.5 If*] and LS III +46 12 as another early O-type system [O4.5
V((f))]. We measure a 97.2-day period for LS III +46 11 and derive
minimum masses of 38.80 ± 0.83 M⊙ and 35.60
± 0.77 M⊙ for its two stars. We measure the
extinction to both stars, estimate the distance, search for optical
companions, and study the surrounding cluster. In doing so, a variable
extinction is found as well as discrepant results for the distance. We
discuss possible explanations and suggest that LS III +46 12 may be a
hidden binary system where the companion is currently undetected.
Related projects
The IACOB project: A new Era in the Study of Galactic OB Stars
IACOB is an ambitious long-term project whose main scientific goal is to provide an unprecedented empirical overview of the main physical properties of Galactic massive O- and B-type stars which can be used as definitive anchor point for our theories of stellar atmospheres, winds, interiors and evolution of massive stars
Sergio
Simón Díaz