The early-type massive binary MQ Cen (P$_{orb}$=3.7 d) has been investigated by means of high-resolution ($Rsim48,000$) spectral analysis and multi-band (Johnson $BVRI$ and Str{o}mgren $vby$) light curve modeling. The physical parameters of the components have been found to be $M_1= 4.26pm0.10$ M$_{odot}$, $R_1= 3.72pm0.05 $R$_{odot}$, $T_{rm eff1}=16,600pm520$ K, and $M_2= 5.14pm0.09 $M$_{odot}$, $R_2= 7.32pm0.03 $R$_{odot}$, $T_{rm eff2}=15,000pm500$ K for the primary and secondary, respectively. The orbital inclination is $i=87.0pm0.2$ deg. The distance to MQ Cen has been derived to be $d=2,460pm310$ pc which locates it in the Crux OB1 association. However, the age of MQ~Cen ($sim70$ Myr) is higher than the one reported for the Crux OB1 association ($sim$6 Myr). The derived masses are implying a spectral type of B5 for the primary and B4 for the secondary component. Nevertheless, the secondary component, which is more massive, appears to be cooler than the primary component: It has completed its lifetime on the main-sequence and it is now positioned at the turn-off point of the giant branch, meanwhile the less massive primary component is still staying on the main-sequence.
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