SMaSH+ survey data yields the first observationally grounded distributions of key parameters for 26 hierarchical massive triples, dominated by tight inner binaries and wider tertiaries with no strong mass-separation correlations.
The VLT-FLAMES Tarantula Survey VIII. Multiplicity properties of the O-type star population
4 Pith papers cite this work. Polarity classification is still indexing.
abstract
Aims. We analyze the multiplicity properties of the massive O-type star population. With 360 O-type stars, this is the largest homogeneous sample of massive stars analyzed to date. Methods. We use multi-epoch spectroscopy and variability analysis to identify spectroscopic binaries. We also use a Monte-Carlo method to correct for observational biases. Results. We observe a spectroscopic binary fraction of 0.35\pm0.03, which corresponds to the fraction of objects displaying statistically significant radial velocity variations with an amplitude of at least 20km/s. We compute the intrinsic binary fraction to be 0.51\pm0.04. We adopt power-laws to describe the intrinsic period and mass-ratio distributions: f_P ~ (log P)^\pi\ (with 0.15 < log P < 3.5) and f_q ~ q^\kappa\ with 0.1 < q=M_2/M_1 < 1.0. The power-law indexes that best reproduce the observed quantities are \pi = -0.45 +/- 0.30 and \kappa = -1.0\pm0.4. The obtained period distribution thus favours shorter period systems compared to an Oepik law. The mass ratio distribution is slightly skewed towards low mass ratio systems but remains incompatible with a random sampling of a classical mass function. The binary fraction seems mostly uniform across the field of view and independent of the spectral types and luminosity classes. The binary fraction in the outer region of the field of view (r > 7.8', i.e. approx117 pc) and among the O9.7 I/II objects are however significantly lower than expected from statistical fluctuations. Conclusions. Using simple evolutionary considerations, we estimate that over 50% of the current O star population in 30 Dor will exchange mass with its companion within a binary system. This shows that binary interaction is greatly affecting the evolution and fate of massive stars, and must be taken into account to correctly interpret unresolved populations of massive stars.
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Southern Massive Stars at High Angular Resolution (SMaSH+): Properties of hierarchical massive triples
SMaSH+ survey data yields the first observationally grounded distributions of key parameters for 26 hierarchical massive triples, dominated by tight inner binaries and wider tertiaries with no strong mass-separation correlations.
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Stellar winds of O-type stars traced by high ionization fine-structure emission lines with JWST/MIRI
JWST/MIRI detects [Ne V] 14.3 micron emission from O-star winds in 5 of 22 observed stars, enabling wind speed and mass-loss rate estimates even in weak-wind regimes.
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A Kinematic Study of Wolf-Rayet Stars at the Galactic Center I: Binary Candidates and Constraints on the Binary Fraction
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