We report the discovery and orbital solutions for two new OB binaries in the Cygnus OB2 Association , MT311 ( B2V + B3V ) and MT605 ( B0.5V + B2.5 : V ) .
We also identify the system MT429 as a probable triple system consisting of a tight eclipsing 2.97 day B3V+B6V pair and a B0V at a projected separation of 138 AU .
We further provide the first spectroscopic orbital solutions to the eclipsing , double-lined , O-star binary MT696 ( O9.5V + B1 : V ) , the double-lined , early B binary MT720 ( B0-1V + B1-2V ) , and the double-lined , O-star binary MT771 ( O7V + O9V ) .
These systems exhibit orbital periods between 1.5 days and 12.3 days , with the majority having P < 6 days .
The two new binary discoveries and six spectroscopic solutions bring the total number of known massive binaries in the central region of the Cygnus OB2 Association to 20 , with all but two having full orbital solutions .