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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 742459.0, MPI für Astronomie / Publikationen_mpia
GRAVITY spectro-interferometric study of the massive multiple stellar system HD 93206 A
Authors:Sanchez-Bermudez, J.; Alberdi, A.; Barbá, R.; Bestenlehner, J. M.; Cantalloube, F.; Brandner, W.; Henning, T.; Hummel, C. A.; Maíz Apellániz, J.; Pott, J. -. U.; Schödel, R.; van Boekel, R.
Date of Publication (YYYY-MM-DD):2017
Title of Journal:The Astrophysical Journal
Issue / Number:1
Start Page:id. 57 (13 pp)
Audience:Not Specified
Abstract / Description:Characterization of the dynamics of massive star systems and the astrophysical properties of the interacting components are a prerequisite for understanding their formation and evolution. Optical interferometry at milliarcsecond resolution is a key observing technique for resolving high-mass multiple compact systems. Here, we report on Very Large Telescope Interferometer/GRAVITY, Magellan/Folded-port InfraRed Echellette, and MPG2.2 m/FEROS observations of the late-O/early-B type system HD 93206 A, which is a member of the massive cluster Collinder 228 in the Carina nebula complex. With a total mass of about 90 {M}ȯ , it is one of the most compact massive quadruple systems known. In addition to measuring the separation and position angle of the outer binary Aa–Ac, we observe Brγ and He i variability in phase with the orbital motion of the two inner binaries. From the differential phase ({{{Δ }}}φ ) analysis, we conclude that the Brγ emission arises from the interaction regions within the components of the individual binaries, which is consistent with previous models for the X-ray emission of the system based on wind–wind interaction. With an average 3σ deviation of {{{Δ }}}φ ∼ 15^\circ , we establish an upper limit of p ∼ 0.157 mas (0.35 au) for the size of the Brγ line-emitting region. Future interferometric observations with GRAVITY using the 8 m Unit Telescopes will allow us to constrain the line-emitting regions down to angular sizes of 20 μas (0.05 au at the distance of the Carina nebula).
Free Keywords:astrometry; binaries: general; stars: massive; techniques: interferometric
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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