The original paper is at https://arxiv.org/abs/2310.20634

It seems from the article that GEMs are an interesting research area, but it doesn’t explain why. Could anyone ELI5?

A planetary/life theory suggests Jupiter and Saturn are the protectors of the inner planets. These huge gas giants capture large solid masses whizzing around in space and either swallow those masses or turn them into moons. Without these giants acting like the solar system's vacuum cleaners, it's much more likely for an inner planet like Earth to be struck and destroyed, which would be catastrophic for life on that inner planet.

So assuming life in the universe takes a similar form to ours (liquid water, stable star) if we look for solar systems like ours with big outer vacuum cleaner planets, the chances of any inner planets in the Goldilocks zone having life are higher.

I thought this was going to be about the detection of a giant ring system around an exoplanet, but it's merely in reference to diameter and mass. Maybe that's a particularly interesting size for an exoplanet but as far as I know it's not.

wow, that is disappointing, as Saturn is much more known for its rings than its size. Yes, most people will know Saturn is much larger than Earth, but "Survey Says!" top response on the board will be "rings". Jupiter would probably be "storm" or "big" would be my guess.

> It seems hard to detect planets that are in the life zone (not too far, not too close) and small enough to be somewhat similar. reply

Maybe this is why we (presumably) haven't been detected ourselves.

Saturn should be known for being undense enough to float.

I was recently saddened by a response in the thread about the Euclid's first images that HN is not an astronomy forum, and that the audience needs to be explicitly told that a wide angle telescope is different from a wide angle camera lens on your mobile device.

So no, after that reset of expectations, I wouldn't expect Saturn's density to be widely known. Hell, I'm now starting to wonder if we've even reached the point that Saturn's rings might not even be associated with it at all?!?!

We can barely detect exoplanets, much less rings on them. Even Saturn's rings were only recently better understood.

Does TESS know of any habitable planets in that system?

Define habitable. It seems hard to detect planets that are in the life zone (not too far, not too close) and small enough to be somewhat similar.

One telescope can't watch one star for decades to find planets in larger orbits. All transit-based exoplanet detection will naturally bias towards detection of large planets in short orbits around small stars.