===== Ultra-compact binaries section =====

==== NGO Yellow book ====
  * Verification binaries
  * Thousands of detections
  * Detect all (tens) NS, BH binaries
  * Binary evolution (Common envelope)
  * Onset mass transfer in WD+WD binaries (stability, mergers, SNIa)
  * Period evolution, physics of tides and mass transfer (not sure this is a strong case)
  * Detections (distances, inclinations) throughout Galaxy --> Galactic structure


==== What will have been done by 2028? ====

  * Gaia discovered few hundred(?) short period binaries (but V < ~20, i.e. only ~25 resolved eELISA sources, cf Littenberg et al. 2013)
  * Variability surveys (OmegaWhite etc, LSST?) will have found many(?) binaries (g < 22?)
  * Pdot measurement of at least J0651 and likely a few others will be exquisite
  * Gaia has mapped structure of Galaxy
  * EM follow-up facilities available? Deep, wide field images (BlackGEM?)
  * SKA likely not found the short period NS+NS (expected only 1/1e4 MSPs or so and signals very smeared out due to short orbital periods)
  * Do we understand binary evolution, common-envelope by 2028?


==== White paper ====

  * Verification binaries (quite a few by 2028 expected)
  * Thousands of resolved binaries (most still undiscovered by 2028) because too faint
  * Detect all (tens) NS, BH binaries, likely not found by SKA
  * Binary evolution, CE?
  * Onset mass transfer in WD+WD binaries (stability, mergers, SNIa)