HD 180555 is a star is a double system.

Other than a double pulsar system, these systems also occur:

The other choice would've been to go outward, but Planet Six is a double system with a common center of gravity.

Our double system will bring the results that we require.

Has a double locking system for extra security and is pressure mounted.

HD 37646 is a star in a double system.

"Oren, do you believe in the double standard system?"

Saddam Hussein has built up a double system of power.

I expect to see debate with the Council over a good few questions, security charges for example, or double check-in systems.

The double circulatory system of blood flow references two distinct and separate systems.