How many planets A, F, G, K and M stars can have?

[Michael Kilderry]

I think it is good to ask for approval, especially if you are no rocket scientist. I think it is better to ask questions now about the realism in the solar system while you're still creating it, because if somebody says later that it couldn't be realistic, and that's what you are aiming for, you'd have to change things about the solar system that you've become attached to as it is.

I am also here to say that I have changed my Proxima Centauri System, it is now a six planet system, consisting of four terrestrials and two gas giants, the most distant planet lies no further from Proxima than 15 AU. The first planet I'm working on is at 0.012 AU, the right distance for the planet to have an Earthly temperature, but instead of looking like Earth, it is about the size of our moon and has two completely different hemispheres thanks to it's tidal locking. The day side is covered in maria and extinct volcanoes, the night side has cracks like Europa, because of the brittle ice covering that side of the surface, this side also has far more craters. This planet is called Unterra because the prefix un- means "not" and terra means Earth, so it's name means "not an Earth". A suitable name for a planet that is at the right distance from it's star, but never became habitable.

Michael Kilderry

[Cormoran]

Michael,

Now Unterra sounds interesting, both conceptually and visually. Whether it could exist is anyone's guess (Paging Dr. G), but think of the evolution of such a world. It was probably rotating in its early life, and may possibly have been Earthlike. How would its slowly extending day affect it? How would its oceans behave as the temperature differential between the two hemispheres increased?

One very interesting question is what does the twilight area look like?

Regards,

Cormoran

[Michael Kilderry]

It obviously was a good idea to start making realistic solar systems, people seem to like them more!

Unterra would have been more earthlike in it's distant past, but it is too small to hold an atmosphere for long periods of time and was doomed to be tidelocked!

I am really no rocket scientist, but as the days slowly lengthened, and the atmosphere became thinner, the daytime would have became hotter and the nighttime would have became cooler until than icecap grew on the night side and the water boiled away on the day side. I may include some watery areas on the planet's terminator, as that area would still be balanced at a normal temperature.

What makes things much more interesting is that Unterra's orbit is a bit inclined therefore the poles of the planet go through seasonal daytime and nighttime, there would be no water of ice here, it would have boiled away during the periodic day.

Michael Kilderry