The binary merger channel for the progenitor of the fastest rotating O-type star VFTS102

Abstract

VFTS102 has a projected rotational velocity ($>$500\,km s${}^{-1}$) and would appear to be the fastest rotating O-type star. We show that its high rotational velocity could be understood within the framework of the binary merger. In the binary merger channel, the progenitor binary of VFTS102 would evolve into contact while two components are still on the main sequence, and then merge into a rapidly rotating single star. Employing Eggleton's stellar evolution code, we performed binary stellar evolution calculations and mapped out the initial parameters of the progenitor of VFTS102 in the orbital period-mass ratio ($P-q$) plane. We found that the progenitor binary of VFTS102 with initial mass ratio $q_0 \la 0.7$ should have an initial orbital period shorter than $3.76-4.25$\,days, while above this mass ratio it should have an initial orbital period shorter than $1.44-1.55$\,days. The progenitor of VFTS102 would evolve into contact during the rapid mass transfer phase or during the subsequent slow mass transfer phase, and might ultimately merge into a rapidly rotating massive star. In addition, we performed Monte Carlo simulations to investigate the binary merger channel. We estimated the fraction of binaries that would merge into single stars and the fraction of single stars that might be produced from the binary merger channel. It is found that about 8.7% of binaries would evolve into contact and merge into rapidly rotating single stars, and about 17.1% of single stars might be produced from the binary merger channel and should have similar properties to VFTS102. This suggests that the binary merger channel might be one of the main channels for the formation of rapidly rotating massive stars like VFTS102.

16 pages, 3 figures, Accepted for publication in Monthly Notices

References in corpus (13)

• Binary interaction dominates the evolution of massive stars
• Pre-Supernova Evolution of Massive Single and Binary Stars
• The High Angular Resolution Multiplicity of Massive Stars
• The VLT-FLAMES survey of massive stars: constraints on stellar evolution from the chemical compositions of rapidly rotating Galactic and Magellanic Cloud B-type stars
• Binary star progenitors of long gamma-ray bursts
• The VLT-FLAMES survey of massive stars: atmospheric parameters and rotational velocity distributions for B-type stars in the Magellanic Clouds
• Efficiency of mass transfer in massive close binaries, Tests from double-lined eclipsing binaries in the SMC
• The different progenitors of type Ib, Ic SNe, and of GRB
• The dynamical stability of W Ursae Majoris-type systems
• Primordial Binary Evolution and Blue Stragglers
• On the minimum mass ratio of W UMa binaries
• Constraints on rotational mixing from surface evolution of light elements in massive stars
• Binary coalescence from case A evolution -- mergers and blue stragglers

Cited by in corpus (9)

• On the formation of Be stars through binary interaction
• MY Camelopardalis, a very massive merger progenitor
• Binary interactions as a possible scenario for the formation of multiple stellar populations in globular clusters
• Extreme mass ratios and fast rotation in three massive binaries
• The First Photometric Study of the Short-period Shallow Contact System LO Comae
• The Transformative Journey of HD 93521
• HST/COS Spectra of the Wind Lines of VFTS 102 and 285
• Two twin binaries with nearly identical components: KIC 4826439 and KIC 6045264
• Spectroscopic Line Modeling of the Fastest Rotating O-type Stars