Melnick 33Na: a very massive colliding wind binary system in 30 Doradus

Abstract

We present spectroscopic analysis of the luminous X-ray source Melnick 33Na (Mk 33Na, HSH95 16) in the LMC 30 Doradus region (Tarantula Nebula), utilising new time-series VLT/UVES spectroscopy. We confirm Mk 33Na as a double-lined O-type spectroscopic binary with a mass ratio $q=0.63\pm 0.02$, $e=0.33\pm 0.01$ and orbital period of $18.3\pm 0.1$ days, supporting the favoured period from X-ray observations obtained via the Tarantula -- Revealed by X-rays (T-ReX) survey. Disentangled spectra of each component provide spectral types of OC2.5 If* and O4 V for the primary and secondary respectively - unusually for an O supergiant the primary exhibits strong CIV 4658 emission and weak NV 4603-20, justifying the OC classification. Spectroscopic analysis favours extreme physical properties for the primary ($T_{\mathrm{eff}}=50$ kK, $\log L/L_{\odot }=6.15$) with system components of $M_1=83\pm 19M_{\odot }$ and $M_2=48\pm 11M_{\odot }$ obtained from evolutionary models, which can be reconciled with results from our orbital analysis (e.g. $M_1{\sin }^{3}i=20.0\pm 1.2M_{\odot }$) if the system inclination is $\sim 38^{\circ }$ and it has an age of 0.9 to 1.6 Myr. This establishes Mk 33Na as one of the highest mass binary systems in the LMC, alongside other X-ray luminous early-type binaries Mk34 (WN5h+WN5h), R144 (WN5/6h+WN6/7h) and especially R139 (O6.5\,Iafc+O6\,Iaf).

Accepted for publication in MNRAS, 16 pages and 14 figures plus supplementary material

References in corpus (17)

• Binary interaction dominates the evolution of massive stars
• Pre-Supernova Evolution of Massive Single and Binary Stars
• A distance to the Large Magellanic Cloud that is precise to one per cent
• BONNSAI: a Bayesian tool for comparing stars with stellar evolution models
• The evolution of rotating very massive stars with LMC composition
• The Tarantula Massive Binary Monitoring: I. Observational campaign and OB-type spectroscopic binaries
• The VLT-FLAMES Tarantula Survey XVII. Physical and wind properties of massive stars at the top of the main sequence
• The VLT-FLAMES Tarantula Survey XVI. The optical+NIR extinction laws in 30 Doradus and the photometric determination of the effective temperatures of OB stars
• A Spectroscopic Survey of WNL Stars in the LMC: General Properties and Binary Status
• The Massive Star-forming Regions Omnibus X-ray Catalog
• The Tarantula Massive Binary Monitoring: III. Atmosphere analysis of double-lined spectroscopic systems
• Mass loss and the Eddington parameter: a new mass-loss recipe for hot and massive stars
• Towards an Accurate Determination of Parameters for Very Massive Stars: the Eclipsing Binary LMC-SC1-105
• Weighing Melnick 34: the most massive binary system known
• The Tarantula Massive Binary Monitoring V. R 144: a wind-eclipsing binary with a total mass > 140 Msun
• A modern study of HD166734: a massive supergiant system
• Mapping the core of the Tarantula Nebula with VLT-MUSE II. The spectroscopic Hertzsprung-Russell diagram of OB stars in NGC 2070