Anyone placed a 3rd companion in Book 6?

[whartung]

Has anyone placed a 3rd companion star (not a Far star) in to a system using Book 6?

How did you go about it? The workflow is pretty tied to only 2 stars. Even the later editions (MT, TNE, which are pretty much 95+% Book 6) are still pretty muddy on a 3rd companion and it's impact in the system.

From the text:

If a companion is present, certain restrictions on available orbits exist. Orbits closer to the primary than the companion's orbit must be numbered no more than half of the companion's orbit number (roundfractions down). Orbits farther away than the companion must be numbered at least two greater than the companion's orbit number.

For example, in a system with a companion in orbit 2, orbit 0 is available, and orbits 4 and higher are available. In a system with a companion at orbit 5, orbits 0, 1 and 2 are available, and orbits 7 and higher are available.

So in the above example, were there both companions, the one in orbit 2, and the on it orbit 5, I guess at the end of the day, orbit 0 and orbit 7+ remain as being available.

The second companion could not fit on orbit 4 (as it's in theory unavailable due the companion in orbit 2). OR, if they generate close together, we could fuse them like we do Close orbits and the primary.

I guess you just keep placing the second companion until it doesn't conflict with the first. It seems that the restrictions on available orbits should be changed somehow for the outer orbits. This rule treats them linearly (i.e. the distance between orbit 1 and 2 is the same as between 5 and 6), but that's not the case.

MT and TNE have this A-B table which makes no sense to me for 3 bodies.

Just curious how others have approached this.

 

[Spinward Flow]

For convenience, let's take a simple example (to keep things clearer) of:
Primary
Companion (orbit 2)
Companion (orbit 10)

From the text:

If a companion is present, certain restrictions on available orbits exist. Orbits closer to the primary than the companion's orbit must be numbered no more than half of the companion's orbit number (roundfractions down). Orbits farther away than the companion must be numbered at least two greater than the companion's orbit number.

For example, in a system with a companion in orbit 2, orbit 0 is available, and orbits 4 and higher are available. In a system with a companion at orbit 5, orbits 0, 1 and 2 are available, and orbits 7 and higher are available.

So what we have is:

• Primary
• Orbit 0 = Available
• Orbit 1 = Not available (due to Companion 1)
• Orbit 2 = Companion 1
• Orbit 3 = Not available (due to Companion 1)
• Orbit 4 = Available
• Orbit 5 = Available
• Orbit 6 = Not available (due to Companion 2)
• Orbit 7 = Not available (due to Companion 2)
• Orbit 8 = Not available (due to Companion 2)
• Orbit 9 = Not available (due to Companion 2)
• Orbit 10 = Companion 2
• Orbit 11 = Not available (due to Companion 2)
• Orbit 12 = Not available (due to Companion 2)
• Orbit 13 = Not available (due to Companion 2)
• Orbit 14 = Not available (due to Companion 2)
• Orbit 15 = Not available (due to Companion 2)
• Orbit 16 = Not available (due to Companion 2)
• Orbit 17 = Not available (due to Companion 2)
• Orbit 18 = Not available (due to Companion 2)
• Orbit 19 = Not available (due to Companion 2)
• Orbit 20 = Available

A type Ia, Ib or II primary star that rolls 2D+8=12+8=20 for maximum orbits could have a planet all the way out at Orbit 20 (per LBB6 p23) ... and Orbits 4 and 5 tend to be Inner Zone (or inside the star itself!) with these types of stars.

Note that according to the chart (LBB6 p31) it is possible for a K5 V or M0 V primary star to have a planet in the Orbit 0 habitable zone plus 2 additional companion stars in the system, provided the nearest companion star to the primary is in Orbit 2+. In such a system it would be perfectly possible to have a habitable planet at Orbit 0, and two additional companion stars in Orbits 2+.

Alternatively, a K0 VI primary star could have a habitable planet in Orbit 1, with any companion stars in orbits 3+. So you could (theoretically) wind up with an arrangement like this:

• K0 VI Primary (0.43 solar masses)
• Orbit 0 = available (inner)
• Orbit 1 = mainworld (habitable)
• Orbit 2 = empty
• Orbit 3 = DA Companion (0.36 solar masses)
• Orbit 4 = empty
• Orbit 5 = empty
• Orbit 6 = Planetoid Belt (outer)
• Orbit 7 = Gas Giant (outer)
• Orbit 8 = empty
• Orbit 9 = empty
• Orbit 10 = empty
• Orbit 11 = empty
• Orbit 12 = empty
• Orbit 13 = empty
• Orbit 14 = M9 V Companion (0.215 solar masses)

Note that this is a total of 1.005 solar masses just for the stars in this system (and obviously a lot fewer planets than the Sol system), and the DA companion star could even be a "captured star" that is inclined away from the ecliptic that wandered (blundered?) into the system after its formation, kicking out some of the planets between the gas giant and the primary and disturbing the planetoid belt to orbit above and below the system's natural ecliptic plane in more of a "cloud" formation of complex orbital resonance frequencies (so not a "flat" belt in the plane of the ecliptic). That way the (eccentric) DA companion is "not native" to the overall formation of the star system and the mainworld probably migrated inwards to its present (stable for now) orbit.



Hope these examples help you with interpretation of the Rules As Written (RAW).
If you like the K0 VI Trinary system outlined above enough to use it somewhere ... have at it.

 

[whartung]

Yea, it just seems that the second companion pretty much crushes the system. In your example it's consuming 13 "orbits" (which, in theory, is thousands of AU in size) whereas the first one consume just 3 orbits (and less than an AU).

 

[Spinward Flow]

True. Orbit 8 is 19.6 AU ... and Orbit 14 is 1229.2 AU according to LBB6.

Remove the Planetoid Belt and move the Gas Giant inwards to Orbit 6 (5.2 AU) and the outer companion M9 V Companion star could be in Orbit 12 (307.4 AU) ... which is still WAY OUT THERE yet still "reasonable" as far as these things go.

Yea, it just seems that the second companion pretty much crushes the system.

True ... but that's kind of to be expected in a trinary system, no?

 

[whartung]

True ... but that's kind of to be expected in a trinary system, no?

Heck if I know, I haven't broke out the "Home Solar System Kit -- now with Real Fuzion(tm)" in a long time.

Looking at other systems, they pretty much just punt the 3rd companion deep out in to the dark.

 

[Spartan159]

I'm tempted to steal ready made systems from Elite: Dangerous

 

[willtron3030]

[Still shilling for "Architect of Worlds" by John Ziegler. He's also produced a slightly abbreviated version for Traveller.]

My take, as regards your question, is that no star strictly has two companions. A binary system can have a more distant companion, or a primary may have a companion binary system.

Start with the primary, and add a companion. Now there are two stars, ostensibly orbiting one another, but actually orbiting the barycenter, or center of mass: (A B). A and B may each have S-type planets orbiting them (if the stellar pair is far enough apart), or may have P-type planets orbiting the barycenter (If the pair is close enough together).

If we add a third star, it's going to be either replace one of the stars with another pair, or it will orbit the original binary.
(A B) plus C --> (A (B C)) | ((A B) C)

Even after coding a generator based on AoW and kludging the calculation of insolation for circumbinary planets, it's rare to come up with a habitable temp planet in a binary or trinary system unless one star is hundreds of AU away from the other(s).

 

[Spinward Flow]

Reposting the Anton Petrov youtube video that addresses this issue the best that I've seen (and it's relevant to the topic).

The key point (about 3:20 in) is that star systems of multiple stars ALWAYS wind up being combinations of binaries.
So a combination of 4 stars would wind up being two pairs of binaries that orbit each other as binary pairs.
For example: (A+B) orbiting (C+D)

Anyway, the animation graphics in the video help visualize what's going on in a very intuitive way, so if you're having trouble picturing what it would look like in your mind's eye, the above video ought to help with that tremendously (picture worth 1000 words and all that, with moving pictures being worth even more!).

 

[Bartleby]

I didn't know about Architect of Worlds, so I will look that up. Thank you.

 

[Bartleby]

I am updating my sector builder code to use all of the First In rules, but that is getting long in the tooth now and, short of a brand new comprehensive detailed model, I am looking on how to adjust it to make it as "realistic" as possible. Or at least minimize the lack of realism until I deem it necessary.

 

[willtron3030]

I didn't know about Architect of Worlds, so I will look that up. Thank you.

architect of worlds – Sharrukin's Palace

wordpress.sharrukinspalace.com

 

[Bartleby]

I am now a patron! Thank you. And not only is his work perfect for updating the First In model I have been using, it turns out he is the original First In author. So this is fantastic.

 

[whartung]

All the input is appreciated, but this is more a RAW process question that anything to do with, you know, cosmology.

 

[whartung]

So, it also looks to me if a system has a Far companion, that Far companion can itself be a Trinary system. I don't see any DMs to the Nature table that says it can't.

If a companion is far, it may itself have a companion: roll again on the basic nature column for this far companion. If the result is binary, then the star has a companion- generate it as other companions are generated, but with a DM - 4 on companion orbit.

I assume that both orbits are -4? If it's a trinary?

So, in theory, a system could have 7 stars in it, correct?

A trinary system, with two companion systems, that are both trinaries. But the buck stops there since none of the companion systems can have "Far" orbit companions.

MT has a clause to add a -1 DM to the System Nature table when rolling for a far companion, so perhaps it's worth keeping that.

But "RAW" Book 6, it seems 3 trinaries are possible.

 

[aramis]

Has anyone placed a 3rd companion star (not a Far star) in to a system using Book 6?

How did you go about it? The workflow is pretty tied to only 2 stars. Even the later editions (MT, TNE, which are pretty much 95+% Book 6) are still pretty muddy on a 3rd companion and it's impact in the system.

I remember I always rolled type for all three, then rolled the orbits for the two companions, and if in the same or the larger of the two companion's exclusion zone (which requires using the planetary orbits table and the tables of zones), I made them a binary portion of the trinary. I then added the exclusion zones together (again using the planetary orbits table)

Noting that I once rolled a trinary with a far with a trinary... which, when I first saw a Firefly 'Verse map, screamed at me, "Hey, that looks like a Bk6 system!" (but my mind had been poisoned with "Firefly is Traveller" by COTI...)

 

[whartung]

For the moment, I roll the second companion normally, then I take the remaining orbits and see if I can "fit" the 3rd in to it (given all the criteria of the exclusion zone that gets bigger as the potential orbit gets bigger). If I can, I make a note, and in the end choose one of those orbits (I've seen one case where the 3rd companion ended up inside of the 2nd, surprising, but it fit).

If I can't find that it fits anywhere, I punt it out to Far and be done with.