α (left) and σ_β (right) as a function of 〈e〉 and F_p for binary (top) and triple (bottom) populations. White regions are F_p−〈e〉 pairs that cannot be generated by any α−σ_β pair. Purple curves are the parameter space region in which α = 2, 1, 0 for solid, dotted and dashed, respectively. Green curves are the parameter space region in which σ_β = ∞. Black star is the solution for randomly distributed mutual inclination and eccentricity. White box point with error bars is the and 〈e〉^obs observation values derived in Sect. 2.4. Red circle points are F_p−〈e〉 pairs measured in the four Bate (2019) molecular cloud collapse simulations with different metallicities.