Vol. 563
In section 7. Stellar structure and evolution

The yellow hypergiant HR 5171 A: Resolving a massive interacting binary in the common envelope phase

HR5171 is a binary containing a yellow hypergiant. These are massive stars in a short-lived phase of their evolution. The authors present interferometric observations that are able to resolve the system. They show that the binary is a contact or over-contact system, making it one of the few resolved systems caught in a phase of mass transfer.