These are all very nice pictures
Thanks.
1. Terran moon of a gas giant, with life on it.
2. Same system as the first picture, take a look at the atmospheric pressure and consider that Venus's atmospheric pressure is 92 atmospheres. One could literally swim in that thick of an atmosphere, provided that it doesn't crush you first of course.
3. Classic tidally locked planet.
4. Morning on a living terran planet around an A5 V white main sequence star. Honestly though, arent A spectra stars too short lived for life to really evolve? Anyways, this star happened to be called UMa, so its in the Ursa Majoris constellation, but which one, I have no clue.
life could have come from another planet/object (abiogenesis)
using the mass-lum relationship, the lifespan of an a5v star with mass of 1.8 solar masses can be calculated to be about 2.3 billion years (plus or minus several hundred million years).
it's uncertain how long it takes life to evolve because we only have one example, and there could be great variations depending on the environment. i would guess 2.3 billion years may not be enough for intelligent (sentient) life to evolve on it's own.
For abiogenesis (or maybe you're mixing it with panspermia?), if you're talking about the cold (more like frozen, unless the liquid is something other than water) terran planet, theres the problem of what form or how life would evolve on such a cold world. Alternatively, it could be an Europa analog.
For the planet with an A5 V spectral type sun, it seemed to have even less water than Mars since the water present were in various big lakes. I figured that life on it would still be microorganisms.
Also, there are hints that life actually started very early, within several hundred million years after the Earth formed (or at least after the late heavy bombardment anyway). It's just the long lead time between life getting started and multicellular organisms evolving that makes it seem like A spectra stars wouldn't allow higher life forms a chance to evolve.
Oh yeah, for the tidally locked world, that one has two selene size moons (649km and 789km diameter), and I'm not sure if those would be enough to subtly keep a rotation going for the planet.
