Two potentially life-friendly planets found orbiting a nearby star

How common are "life-friendly" planets (Let's say: on a ratio of Life-Friendly Planet:Non Life-Friendly Planet)? And is there any way to check if life-friendly planets contain life without actually going there?

I was under the impression that planets to be life-friendly have to be close to their red dwarf star to a point they'll be tidally locked (one side always light other night), meaning their atmosphere would freeze on the dark side and planet would end up without an atmostphere.

A good question. No sarcasm, it depends on your definition of "life friendly". Right now, we can't see much more than an orbit and a mass for these things. (There's a spectrum on a few of them, but AIUI for most exoplanets we're still just getting them from star wobbles, which gives us only orbit and mass.) Combined with the stats for the stars themselves, we can say whether or not they could conceivably be in the "liquid water" zone.

But we can't say that they are definitely suitable for life. If Venus and Mars were found orbiting other stars, the press release would declare they could be "life-friendly"; if you squint a bit, both are at least on the edge of where you could get liquid water under the right circumstances. Being much closer to the real Venus and Mars, we know they are both not actually great candidates, because we can see the details that prevent them from being useful clearly.

So I'd say "life-friendly" is a continuum, and kinda relative to the amount of knowledge we have about the planet, which for most exoplanets right now, is very low, making the "life-friendly" bar correspondingly low.

Detecting life in general is impossible; we are fairly sure Earth has had life on it in the past that did not meaningfully change the spectrum of Earth. However, there are some signatures that would be very, very, very suggestive. From what I've gathered, Earth's atmosphere containing free oxygen isn't quite proof of life from a single snapshot, as there are conceivably processes that could produce it momentarily, but having oxygen in our atmosphere consistently for millenia and eons is difficult to explain with anything other than life.

Maybe you meant to say Earth is anti-human. Earth is incredibly life friendly. There's been five previous mass extinction events and each time life has rebounded amazingly.

> Teegarden’s star is a stellar runt that’s barely 9 percent of the sun’s mass. It’s known as an ultra-cool M dwarf

Is it too late to change the name to Tyrion Lannister?