Fastest (and Most Compact) Stellar Spinner Confirmed 47
gregg writes "HM Cancri has been confirmed as a binary system of two white dwarfs orbiting each other so closely that they complete one orbit every 5.4 minutes; they are separated by a mere 8 Earth diameters. 'These are the burnt-out cinders of stars such as our Sun, and contain a highly condensed form of helium, carbon and oxygen. The two white dwarfs in HM Cancri are so close together that mass is flowing from one star to the other. HM Cancri was first noticed as an X-ray source in 1999, showing a 5.4 minutes periodicity, but for a long time it has remained unclear whether this period also indicated the actual orbital period of the system. It was so short that astronomers were reluctant to accept the possibility without solid proof. '"
Tidal bulges (Score:4, Insightful)
Re:Mass flow is common. (Score:2, Insightful)
If you make a closed box around the two white dwarfs and move mass from one to the other you will see that the center of gravity does not change and so I would not think anything would go flying off. Rather both bodies would just move toward the center of gravity while the larger one got larger and the smaller got smaller. If they collided with some force stuff could be thrown away from the collision, but no escape velocity could be reached without another force being involved.