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

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?

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)