Fair enoughIt is different. Any object that is gravitationally round by it's own gravity is considered a planet in this timeline (think Pluto, Ceres, Eris, Sedna, etc, added to the planet list) I have always very much disagreed with the IAU standards. I will not accept the idea of Dwarf Planets not being considered planets. Personal bias and subjectivity, I know, but, it's the way I see these things.
I mean that, as the smallest of them, Nox would still just be visible; the Pluto- and Eris-sized moons, being bigger than Nox, could probably also be detected, and Prosperina would be even easier. However, I think it's right to not include any moons smaller than Nox, because below that threshold they would become harder to detect.Similar in Mass. If you are saying that Nox is the only one that would be large enough to be visible, I do not know about that. I do not know anything about orbital mechanics or how visible these sorts of things would be in space, that's for someone with more talent and knowledge than I to figure out.
Sounds reasonable. A minor moon orbiting within a few hundred km of the surface (working with my estimate of 2.6 R⊕) would have an orbital period of 2 hours 21 minutes.Yes they do. I imagine Minthe's main moons are similar in composition to that of Kuiper belt objects. All icy, with the major ones being cryovolcanic like Enceladus. I am also imagining that because of Minthe's lack of a substantial atmosphere, the rings themselves extend fairly close down to the planet. I would imagine that the record of "Moon with a shortest orbital period around a planet" would be one of Minthe's inner minor moons, likely a small moon similar to that of the moons of Saturn that inhabit it's rings. Going around the planet in mere hours.
Given the luminosity value, WolframAlpha says it would have absolute bolometric magnitude (i.e. the entire spectrum, including infrared) of 12.7, and apparent bolometric magnitude of around -0.4. To convert this to visual magnitude, I'll assume, as you said, Nemesis is similar to Teegarden's star - its visual magnitude is about 5 more than bolometric magnitude. This gives an apparent visual magnitude (i.e. visible light) of +4.6, which makes it a naked-eye star, although not a very prominent one, and I think it would be reasonable to not have it be discovered until the early modern era.There should have been 5, but you are right, I only listed four. The main 4 I listed are the names that matter. Perhaps I can think of more planets for Nemesis, but I am not sure what else to add to it. What magnitude would Nemesis be?
Ok. So we observe Lethe transiting every 21 years? When did we discover it? Is that why we know so little, because we've had so few opportunities to observe it? When was Lethe's most recent transit?Perhaps they would. We can say that the orbital plane of the Nemesis system is tilted so transits are able to be observed like around other stars.
Do all 4 (5?) of the planets transit?
It sounds a bit like some theories for TRAPPIST-1b, although maybe not quite as hot. I like it!My intentions for the first planet is for it to be a hothouse world similar to Venus. Intense atmospheric pressure. Intense heat. Thick atmosphere. Likely hotter than Venus, possibly.
Oh, like Mercury! Interesting idea. I don't know much about Mercury's spin-orbit resonance, but I think that it has to do with its high orbital eccentricity. I don't know if this planet would be very stable with high eccentricity; my instinct is that a planet this close to its star should have almost zero eccentricity, but GJ667C has a planet nearly as close as this with eccentricity around 0.1. Apparently, it's not unreasonable to have a 3:2 spin : orbit resonance there.I would propose that this planet is in a 2:3 resonance, so for every 2 times it orbits, it rotates 3 times. But I do not know if this is possible. If it's not, then we'd have a terminator line where liquid water is present.
This would be possible, it seems, but if you do want the 3:2 resonance, then the orbit should be eccentric, which probably means Cocytus should have an eccentric orbit as well for stability. If that's too complicated or not what you're going for, you could either (a) ignore the lack of realism and do whatever you want (always a fun choice, and you're making this up anyway) or (b) just make it tidally locked.
21 years is perfectly reasonable.I simply put that "21 years" in since I didn't know what else to put.
We have our innermost two planets with 1.2 and 5.7-day orbits. This is very close to 5:1; if we change the outermost orbit to 6.0 days, then 6.0/1.2 = 5, then we get a 5:1 mean motion resonance. This adjustment to the orbital period of Acheron also happens to set up another 5:1 resonance with Cocytus. Then, the overall resonance would be 25:5:1.I wanted to have a resonance, but I do not have the manners to calculate that.
Generally, mean motion resonances are as simple as that; just deciding on a ratio of small whole numbers, and then adjusting your orbital periods to match.