Well. This is quite a pearl.

I don't have time to read a 16-page paper in detail, but I did want to know how the host star compares to everyone's favourite local solitary K-type dwarf, Epsilon Eridani. It's slightly less massive (~0.7 solar mass versus 0.8 for ε Eri) and quite a bit less bright (difference of about 0.1 solar luminosity), but I especially wanted to know about the age of the star. ε Eri is quite young and frothy, but the investigators here infer from the star's motion that it belongs to the thin disk, up to a whopping 10 billion years old.

So we are definitely not talking about an ε Eri-type system. So that should be mean no dust disks, no crazy activity from the star, and no newish planets still carving out their places through the system.

You've really got to wonder about such an old planet, however cold and quiescent it may be. The potential paths for climatic evolution on such a world boggle the mind, however cold it is. You could get an episodically or formerly active world like Mars, a beautifully unstable oscillatory world like Earth, or something completely different. Assuming any atmosphere, of course (safe assumption?). And that's without considering whether there are any other planets in the system.

I really wouldn't spend too much time thinking about this candidate detection, as we have literally seen just the one transit, and we will need to observe this fellow for a while to confirm the discovery, learn about other planets in the system, and so on. The investigators themselves note that the transit was shallow (meaning difficult to detect), but the good news is that the host star is fairly bright, well within reach of amateur equipment. I wonder if citizen scientists will be able to follow the transits.

Exciting times.