Of course they went for an easy gas giant target first (it has lots of water, which is great), but those Earth-like planets in the Goldilocks zone are gonna be some of the most exciting stuff that comes out of this. Looking forward to it.
An obvious target for the coronagraph for regular imaging, but there's no way to get a transmission spectrum of its atmosphere.
The real problem is that Prox c. b is only 0.04 AU out from its host star. So the absorption spectra for a star lined up with the planet is going to be pretty well contaminated with light from Prox c. You could imagine various schemes for moving around the observer for the best angle or big occultation disks, but at a certain point it's going to be easier to just fly a probe over and sample the atmosphere directly.
"Over the coming year, researchers will use spectroscopy to analyze the surfaces and atmospheres of several dozen exoplanets, from small rocky planets to gas- and ice-rich giants. Nearly one-quarter of Webb’s Cycle 1 observation time is allocated to studying exoplanets and the materials that form them." - https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-...
Really, they should be already building 2nd James Webb. I am sure even 10 of them would get 100% utilization for their whole lifetime. I can only imagine what kind of needless political game is happening around prioritization of time slots for it.
Or start working on next-gen, bigger, more resilient etc. It costs peanuts compared to any significant CERN upgrade and we have so much room to progress in astronomy (aka understanding our home, this universe) just by getting more data and resolution.
Super happy we have one JWST, and I hope fervently that it will outlast its original mission by a large fraction, every sign right now points in that direction.
I like to point out that Microsoft could have paid for seven JWSTs (development costs and all) with what they paid for one Activision.