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Appendix A: Interferometric observations

	Fig. A.1 Square visibilities (left), closure phases (middle) and corresponding reduced χ2 map (right) for the PIONIER observation of 2012-02-24. The corresponding best-fit binary model is shown in red.
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	Fig. A.2 Same as Fig. A.1 for the PIONIER observation of 2012-03-02.
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	Fig. A.3 Same as Fig. A.1 for the PIONIER observation of 2012-03-03.
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	Fig. A.4 Same as Fig. A.1 for the PIONIER observation of 2012-03-05.
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Appendix B: Computation of characteristic times for circularization and synchronization

Appendix B.1: Equilibrium tide

Press et al. (1975) provide explicit formulas. For each component of the binary, we have Here N is the angular rotation velocity of the star, g is its gyration radius (the moment of inertia is defined as g²mR²), R_T is an effective Reynolds number that can be taken ~20, and K and δ are numerical parameters. According to Press et al. (1975), we can typically assume K = 0.025 and δ = 0.1. The other symbols have their meaning introduced above. These formulas are valid for either component of the binary. In each case, m₁ stands for the mass of the star we are considering, and m₂ for the mass of the other star.

Appendix B.2: Dynamical tides

Zahn (1977) gave characteristic times.

The conventions are the same as above. E₂ is a dimensionless constant characteristizing the strength of the dynamical tide. Zahn (1975) provided a table of E₂ and gyration radius at ZAMS for various masses. We interpolated these values for the actual masses and computed the characteristic times, assuming n = N and e = 0.

Appendix B.3: Tidally driven meridional currents

According to Tassoul & Tassoul (1992), the characteristic times in years are (B.5)and (B.6)L is the stellar luminosity and N is a charateristic exponent that can be taken as 10 for stars with a convective envelope, and 0 for stars with a radiative envelope, which is the case here.

© ESO, 2013