Direct Detection of the Tertiary Component in the Massive Multiple HD 150 136 with VLTI

Abstract

Massive stars are of fundamental importance for almost all aspects of astrophysics, but there still exist large gaps in our understanding of their properties and formation because they are rare and therefore distant. It has been found that most O-stars are multiples. HD 150 136 is the nearest system to Earth with >100 M_sol, and provides a unique opportunity to study an extremely massive system. Recently, evidence for the existence of a third component in HD 150 136, in addition to the tight spectroscopic binary that forms the main component, was found in spectroscopic observations. Our aim was to image and obtain astrometric and photometric measurements of this component using long baseline optical interferometry to further constrain the nature of this component. We observed HD150136 with the near-infrared instrument AMBER attached to the ESO VLT Interferometer. The recovered closure phases are robust to systematic errors and provide unique information on the source asymmetry. Therefore, they are of crucial relevance for both image reconstruction and model fitting of the source structure. The third component in HD 150 136 is clearly detected in the high-quality data from AMBER. It is located at a projected angular distance of 7.3 mas, or about 13 AU at the line-of-sight distance of HD 150 136, at a position angle of 209 degrees East of North, and has a flux ratio of 0.25 with respect to the inner binary. We resolved the third component of HD 150 136 in J, H and K filters. The luminosity and color of the tertiary agrees with the predictions and shows that it is also an O main-sequence star. The small measured angular separation indicates that the tertiary may be approaching the periastron of its orbit. These results, only achievable with long baseline near infrared interferometry, constitute the first step towards the understanding of the massive star formation mechanisms.

References in corpus (7)

• The High Angular Resolution Multiplicity of Massive Stars
• Star formation through gravitational collapse and competitive accretion
• UBVJHK synthetic photometry of Galactic O stars
• Interferometric data reduction with AMBER/VLTI.Principle,estimators and illustration
• Tracing the young massive high-eccentricity binary system Theta 1 Orionis C through periastron passage
• Evidence for a physically bound third component in HD 150136
• Three-dimensional orbits of the triple-O stellar system HD 150136

Cited by in corpus (12)

• The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars
• The Galactic O-Star Spectroscopic Survey (GOSSS). III. 142 additional O-type systems
• The Multiplicity of Massive Stars: A High Angular Resolution Survey with the HST Fine Guidance Sensor
• Resolved astrometric orbits of ten O-type binaries
• The Villafranca catalog of Galactic OB groups: I. Systems with O2-O3.5 stars
• X-ray irradiation of the winds in binaries with massive components
• A close encounter of the massive kind
• A Coordinated X-ray and Optical Campaign of the Nearest Massive Eclipsing Binary, delta Orionis Aa: III. Analysis of Optical Photometric MOST and Spectroscopic (Ground Based) Variations
• The little-studied cluster Berkeley 90. I. LS III +46 11: a very massive O3.5 If* + O3.5 If* binary
• Resolving the stellar components of the massive multiple system Herschel 36 with AMBER/VLTI
• Discovery and Characterization of a Rare Magnetic Hybrid $\beta$ Cephei Slowly Pulsating B-type Star in an Eclipsing Binary in the Young Open Cluster NGC 6193
• The outer orbit of the high-mass stellar triple system Herschel 36 determined with the VLTI