[SPACE 4e] System Design help? (star systems that is...)

[Captain-Captain]

Originally Posted by Qoltar

"Back" to this star system ... hhmm... this sort of a TRAVELLER questiuon now but here goes:

Would planetary masking be an issue for a starship jumping in from either JumpSpace or Hyperspace??

Also what are the likely travel times between the 3 planets??

- E.W. Charlton

In Traveller you have two choices. Normal ballistic travel between planets and FTL. If ships can continuously do 1 gee out turn over and 1 gee decelerate it'll vary depending on current planetary distances, but in general: Not take very long.

If you're using a more orbital mechanical travel, the general answer is 'longer than that'.

If you're using Traveller's jump drive to cross a system the answer is 1 week plus time spent getting through planet diameter distance etc.

[Pragmatic]

Originally Posted by Ze'Manel Cunha

What about...

And what discounts the idea of...

I was only approaching it from the perspective of three planets in a row. There are other solutions (double-planets, rosettes, and so on) that have a possibility.

I wish there were a way of getting three planets in a row, but as I've show, even using one extreme (ice age) to the other (it's a dry heat), you'll not get three gardens in a row.

What you can do is tinker with hydrographics and atmospheric mass to get the black-body temperature within the range, and end up with two planets in a row with reasonable temperature ranges (cold and hot, for instance). All you have to do is set the orbits at 1.4 ratio, with a minimum separation of 0.15 AU.

[Ze'Manel Cunha]

Originally Posted by Pragmatic

I wish there were a way of getting three planets in a row, but as I've show, even using one extreme (ice age) to the other (it's a dry heat), you'll not get three gardens in a row.

What about by putting in a Brown Dwarf in the outer region?

[Ze'Manel Cunha]

Originally Posted by ericbsmith

Those have some serious problems because of the high levels of radiation (the gas giants magnetic field funnels stellar radiation right into the moons) and extreme tidal effects.
[...]
Not that it's impossible, but they're far less likely to be habitable.

But you're going on the assumption of close in moons to take advantage of the gas giants' temperature radiation, right?

If we have planets/moons further out in orbit of the gas giant so that they aren't too close to the gas giant's magnetic fields, but all of them within the star's livable band, then while possibly experiencing a more rapid seasonal shift, the planets/moons could be livable.

(Especially if the moons' orbits were perpendicular to the gas giant's elliptic, but we don't need to go there.)

[Pragmatic]

Originally Posted by Ze'Manel Cunha

What about by putting in a Brown Dwarf in the outer region?

I dunno. I haven't gone that far in the system design paperwork. :) I keep trying for three. (And I'm SO upset at Chalker for his Warden Diamond configuration, because I'd LOVE to have four planets in a row. :) )

It might be interesting to have a brown dwarf in the system I'm trying to create... I'm trying to create a trinary system (two very close, and the third
distant), with three or more decent habitable planets close together-ish. (Plus a couple of asteroid belts and a gas giant or three--I have a fondness for Jupiter and Saturn. :) )

[Ze'Manel Cunha]

Originally Posted by Pragmatic

I dunno. I haven't gone that far in the system design paperwork. :) I keep trying for three. (And I'm SO upset at Chalker for his Warden Diamond configuration, because I'd LOVE to have four planets in a row. :) )

Well, you could always follow the John Norman, Gor route, and put them in the same orbits, just offset. *innocent look*

[Qoltar]

What I decided to go with was TWO planets in the True "Life zone" ...with the third outer livable planet as one that is orbiting a Gas Giant.

For the un-informed : John F. Ziegler is the one who wrote G;T FIRST IN He also wrote the recently released GURPS:SPACE 4/e ...so any references to "First In" are sort of out-of-date by comparison.

I will figure out a way that the moon/planet has adequate magnetic fields and such of its own - so that radiation from the Gas Giant is NOt an issue. Also, that world should be "habitable" - but barely so . Its the "Desert worlds" of the three planets being created - and the last to be settled.

Thanks for all the advice! ,

- E.W. Charlton

[Flyndaran]

Why not try a "double planet" in one orbit and the third in the second orbit.
It's not that hard if you make a standard garden the moon of a smallish large garden planet with a low density.

I made Ekeetra with a 0.8 G and 1.2 atm. "orbiting" a low density planet Silosia with 1.0 G and 2.7 atm. made breathable by Ekeetrans from a low O2 content. Tidal locking pushed them into having 13.5 day long days leading to unique circadian rhthyms, but hey that just makes them "special". :)

Made even busier by a mars-sized second moon that still has some volcanism. Nice first extraplanetary base for my little space explorers.

Sorry, I had to brag about my babies. My space campaign has them as the progenitors of intersteller travel.

[Pragmatic]

Originally Posted by Ze'Manel Cunha

What about the double planet suggestion I made, along with a third world in a separate orbit?

And what discounts the idea of three habitable large moons around a gas giant?

Could you do a "trial run" through these scenarios?

That is, I'm interested, and would like to see how it's done by the rules, so that I can apply it to my own star-building. :) So if you can provide examples of how you'd go through the rules and achieve these, I'd appreciate it. Even broad instructions would be helpful.

Thanks!

[Pomphis]

For the moons around a GG you simply put a GG in the life zone and give it 3 standard size terrestrial moons (unlikely to be rolled randomly, but possible). Then you develop the moons like any other Terrestrial. The GG is only there to anchor them in a single orbit. They may well be tidelocked to the GG, but as they still orbit the GG, they will not be tidelocked relatively to the star, so tidelocking will not make them uninhabitable. So the GG may also provide protection against tidelocking.