If you're interested in cataloging those file types in Library so you have all your digital media accessed from Library, you might consider the Any File plugin while waiting for Adobe to implement this suggestion.
Thanks John, I have bought a license and it works almost perfect because there is no thumbnail available in the original files. But I'm happy I can 'see' them now in the Library module.
I have no idea how well these work. But if they let you see FITS thumbnails in Finder / File Explorer, than Any File will use them to show thumbnails in LR Library.
Flexible Image Transport System (FITS) is an open standard defining a digital file format [...]. FITS is the most commonly used digital file format in astronomy.