An Elegant Pas de Deux, Setting Off Waves Ringing Out Across the Cosmos
A particular type of binary in which there is a very large difference in the masses of the two objects. Generally, this will involve a super-massive Black Hole with a mass millions of times that of our Sun, and a Neutron Star or Black Hole with a mass roughly the same as our Sun.
The beauty of an EMRI lies in its simplicity. The central black hole is so massive that it will be almost entirely unaffected by the smaller star. In a binary where the stars have nearly equal mass, on the other hand, both will be distorted in weird—and hard to calculate—ways. For an EMRI, however, the smaller star just doesn't have the pull to effect the larger one. Astrophysicists believe that they understand a lone black hole quite well. Observing an EMRI will give them a chance to test that understanding, as the gravitational waves given off by the smaller star map out spacetime near the larger one. What's more, the inspiral will take much longer than a regular compact binary inspiral, giving them more data to use for their tests.
- The progressively closer encounter of two black holes
- The knocking inspiral of two black holes, as their orbit draws them closer and closer
- The chirping inspiral of two black holes