With the radial velocity method they used, anytime - it's a telescope with a spectrometer that only relies on the planets wobbling the stars around a bit to produce a doppler shift.
> A visual inspection of TESS lightcurves shows no transit of TOI-1338/BEBOP-1c, however, thanks to orbital circulation, transits are expected to occur in due time. Circumbinary orbits exhibit nodal precession. This changes the orientation of a circumbinary planet’s orbital plane with respect to both the binary and the observer. This makes a planet change from a transiting to a non-transiting configuration (15, 30) as has been seen in a few systems (31, 32). Using an analytic criterion (33,34), we find that TOI-1338/BEBOP-1c is guaranteed to eventually transit mainly because the binary is so well-aligned with our line of sight (Ibin = 89.658◦) combined with the rather large size of the primary star (RA = 1.299R⊙). Whilst TOI-1338/BEBOP-1c will eventually transit, we are unable to predict when and how frequently. Its precession period is of order 119 years, during which time there will be two periods of transitability of a duration depending on TOI-1338/BEBOP-1c’s orbital inclination.
Yes, absolutely. It's a close binary, where you can get 90% or more the way to the truth by modelling the stars as a single object at their barycenter. TOI-1338 A is a star slightly larger than the sun, and TOI-1338 B, which is a star with ~a third of Sun's mass orbits it in 14 days. This is basically touching as far as stars go.
