Orbits and Habitable Zones

[ovka]

I am looking references for two different things -- OTU only. There may not be any, I just wanted to check.

1. Main worlds not in the habitable zone. I have checked the trade codes for the 53 sectors on TravellerMap that are listed as at least "In Review" for T5SS. I only see one world with one of the trade classifications that would indicate that it is not in the habitable zone (Co, Fr, Ho, Tu, or Tr). That is world is De'ne'tah (Beyond 1118) which has Fr. Are there other canon examples, perhaps some that don't have those trade classifications?

2. Worlds (not necessarily main worlds) with orbits that do not match up with the Titius-Bode rule. Various versions of Traveller have had rules for eccentric orbits and decimal orbits. CT-B6 shows Neptune in orbit 8.5 (p56). Later versions of Traveller had similar information for Neptune. T5.09 (p. 684) shows the orbital eccentricities for all of the planets (and some other bodies) in our solar system. Are there other canon examples?

Thanks for any assistance you can provide.

Cheers,

Baron Ovka

 

[tjoneslo]

I am looking references for two different things -- OTU only. There may not be any, I just wanted to check.

1. Main worlds not in the habitable zone. I have checked the trade codes for the 53 sectors on TravellerMap that are listed as at least "In Review" for T5SS. I only see one world with one of the trade classifications that would indicate that it is not in the habitable zone (Co, Fr, Ho, Tu, or Tr). That is world is De'ne'tah (Beyond 1118) which has Fr. Are there other canon examples, perhaps some that don't have those trade classifications?

I've been part of the review for some of these worlds. I know there are other canon (or partly-canon) worlds outside of the habitable zone. But they are not marked in the T5SS data. You will have to go read through the text descriptions of worlds in the Spinward Marches, Solomani Rim, and a couple of other sectors that may or may not be canon to find them.

The reason there are worlds in Spinward Marches, Solomani Rim, and Dagudashaag sectors marked with the "Sa" (Satellite) is because the reviewers did exactly that.

2. Worlds (not necessarily main worlds) with orbits that do not match up with the Titius-Bode rule. Various versions of Traveller have had rules for eccentric orbits and decimal orbits. CT-B6 shows Neptune in orbit 8.5 (p56). Later versions of Traveller had similar information for Neptune. T5.09 (p. 684) shows the orbital eccentricities for all of the planets (and some other bodies) in our solar system. Are there other canon examples?

Look at GT:Sword Worlds, it may have one or more of the systems with layouts. There were only two or three systems ever detailed in canon that I was aware of (Terra, Regina, and Vland).

The DGP material did more of that, so checking through the Traveller's Digest issues, and say Vilani and Vargr or Solomani and Aslan may produce more examples. If you have access to them.

 

[ovka]

I've been part of the review for some of these worlds. I know there are other canon (or partly-canon) worlds outside of the habitable zone. But they are not marked in the T5SS data. You will have to go read through the text descriptions of worlds in the Spinward Marches, Solomani Rim, and a couple of other sectors that may or may not be canon to find them.

The reason there are worlds in Spinward Marches, Solomani Rim, and Dagudashaag sectors marked with the "Sa" (Satellite) is because the reviewers did exactly that.

So are you saying, then, that in most cases where we see the Sa trade classification, the intent is that the world is outside the habitable zone (but not Regina, because Regina is specifically stated to be in the habitable zone)?

Look at GT:Sword Worlds, it may have one or more of the systems with layouts. There were only two or three systems ever detailed in canon that I was aware of (Terra, Regina, and Vland).

The DGP material did more of that, so checking through the Traveller's Digest issues, and say Vilani and Vargr or Solomani and Aslan may produce more examples. If you have access to them.

I do have them, thanks. I am thinking that the old CT Boxed Module Belt Strike had system details as well.

Cheers,

Baron Ovka

 

[GypsyComet]

So are you saying, then, that in most cases where we see the Sa trade classification, the intent is that the world is outside the habitable zone (but not Regina, because Regina is specifically stated to be in the habitable zone)?

No. He is saying that codes like the orbit indicators are not automatically generated, but must be added by hand.

That said, nearly any of the airless rockballs you see in sector wide UWP listings are likely to be outside the Hab Zone, simply because they don't need to be, and if that's the best a system has to offer it is probably unpleasant above and beyond not having any air.

 

[ovka]

Ah, OK. I gotcha. Thanks.

Cheers,

Baron Ovka

 

[Garnfellow]

GURPS Traveller: Rim of Fire had climate ratings for all worlds in the Solomani Rim, and these could be translated in the T5 habitat codes. The GURPS systems has many more, fine gradations of climate; T5 only codes extreme conditions.

This had been discussed in the T5SS thread. I know it was one of the many things on Don's list, but have no idea where it is now.

 

[G. Kashkanun Anderson]

Main worlds not in the habitable zone. I have checked the trade codes for the 53 sectors on TravellerMap that are listed as at least "In Review" for T5SS. I only see one world with one of the trade classifications that would indicate that it is not in the habitable zone (Co, Fr, Ho, Tu, or Tr). That is world is De'ne'tah (Beyond 1118) which has Fr. Are there other canon examples, perhaps some that don't have those trade classifications?

Dinom (Spinward Marches 1811) orbits well outside of its primary's Habitable Zone. This is Canon, as it is brought up in the old Double Adventure 'Across the Bright Face' that the world has a 1,600 year orbit. Even for an A4V star like Dinom's primary, that clearly indicates an Outer System orbit.

 

[maksimsmelchak]

I am looking references for two different things -- OTU only. There may not be any, I just wanted to check.

1. Main worlds not in the habitable zone. I have checked the trade codes for the 53 sectors on TravellerMap that are listed as at least "In Review" for T5SS. I only see one world with one of the trade classifications that would indicate that it is not in the habitable zone (Co, Fr, Ho, Tu, or Tr). That is world is De'ne'tah (Beyond 1118) which has Fr. Are there other canon examples, perhaps some that don't have those trade classifications?

Hi Ovka!

The climate codes [habitable zone (Co, Fr, Ho, Tu, or Tr)] are largely unused at this time in 2016.

Newer entries have them, but legacy data typically does not.

The exception might be the Lk and Tz does which show twilight zones with locked climates. I am still trying to figure out the fine distinctions between Lk and Tz or even whether they are intended to have fine distinctions.

The Sa (satellite world) code would definitely be an exception. Thomas Jones-Low has done work with those.

From what I can tell, Hz (habitability) is a factor in T5 system creation, but it doesn't seem to be fully aligned with all of the "real-world" science out there, which would be a near impossible goal since much of that data is constantly changing.

Hope that helps. Interesting topic and question.

Shalom,
Maksim-Smelchak.

 

[whulorigan]

The exception might be the Lk and Tz does which show twilight zones with locked climates. I am still trying to figure out the fine distinctions between Lk and Tz or even whether they are intended to have fine distinctions.

My thoughts:

Tz (Twilight Zone) would specifically refer to a tide-locked world in which the sunward face is too hot and the night-side face is too cold, but the twilight band is habitable.

Lk (Tide-locked) might refer to a world that either the sunward face OR the night side face is habitable, but the opposite face is not. It could possibly also refer to a satellite world that is tide-locked to its Gas Giant, but actually sees the sun on all of its faces as it orbits the Gas Giant.

NOTE: I haven't checked to see if any of the above are explicitly contradicted by the T5 text.

 

[maksimsmelchak]

My thoughts:

Tz (Twilight Zone) would specifically refer to a tide-locked world in which the sunward face is too hot and the night-side face is too cold, but the twilight band is habitable.

Lk (Tide-locked) might refer to a world that either the sunward face OR the night side face is habitable, but the opposite face is not. It could possibly also refer to a satellite world that is tide-locked to its Gas Giant, but actually sees the sun on all of its faces as it orbits the Gas Giant.

NOTE: I haven't checked to see if any of the above are explicitly contradicted by the T5 text.

The T5 text is thick enough that I'm taking time to absorb it.

I always seem to be finding new things in it.

Shalom,
Maksim-Smelchak.

 

[tjoneslo]

Tz (Twilight Zone) would specifically refer to a tide-locked world in which the sunward face is too hot and the night-side face is too cold, but the twilight band is habitable.

It may not match word for word, but this is essentially correct.

Lk (Tide-locked) might refer to a world that either the sunward face OR the night side face is habitable, but the opposite face is not. It could possibly also refer to a satellite world that is tide-locked to its Gas Giant, but actually sees the sun on all of its faces as it orbits the Gas Giant.

This is also essentially correct. I believe it also includes worlds in a 3:2 resonance lock like Mercury. I'm not sure how close to almost Tide locked worlds are counted in this category. For example Venus isn't tide locked but has a very slow rotation period. (the Venus day is 18 earth days longer than the Venus year).

 

[Garnfellow]

In T5, Tz are worlds tide locked to a star, Lk are satellites tide locked to a planetary body, either a gas giant or large terrestrial planet.

 

[Nathan Brazil]

With regards to temperature conversion from GURPS to T5SS, because I do insane conversions. Perhaps these can be a guide:

I have already done conversions for my personal database. Perhaps this will work. However note it is not just temperature, it is orbital position, unless you make the decision that I did that the temperature also implies orbital position.
First T5 defines temperatures like this (Benchmarks p. 541)
to 0 C = Cold (unprotected you take 1 or more pts of damage per minute)
25 C = Human Temperate Environment
50 C + = Hot (unprotected you take 1 or more pts of damage per minute)
Not sure what to tell you about between 1C and 50C. From a nit picky, grognardy point of view, in between is not explicitly stated.

The T5 codes with regards to orbital position are based Bodes Law Orbital Position
HZ -1 Hot (Ho) all worlds if one orbit closer to the star from the Habitable Zone are Hot and have Hot Temperatures, at the limit of human endurance
HZ -1 AND Size 6-9 AND Atmo 4-9 AND Hyd 3-7 are Tropic (Tr)
So all Tr worlds are also Ho worlds. The reverse is not true however.
The temperature for these worlds is considered "Hot" which means 50C+
This implies that worlds with such temperatures are Ho worlds and possibly Tr worlds in an Orbit closer than the HZ

HZ +1 Cold (Co) all worlds if one orbit further from from the Habitable Zone are Cold and have Cold Temperatures, at the limit of human endurance
HZ +1 AND Size 6-9 AND Atmo 4-9 AND Hyd 3-7 are Tundra (Tr)
So all Tu worlds are also Co worlds. The reverse is not true however.
The temperature for these worlds is considered "Cold" which means <0C
This implies that worlds with such temperatures are Co worlds and possibly Tr worlds in an Orbit further than the HZ

HZ +2 Frozen (Fr) "The world lies substantially beyond the Habitable Zone of the system (HZ+2 or greater) and environmental temperatures are well below the freezing point of many gases."

 

[Nathan Brazil]

This works out to this conversion from GURPS IW, GURPS 3 ranges are slightly different
GURPS IW
(Co or Co Tu) Frozen, Very Cold, Cold, Chilly
(No Code used) Cool, Normal, Warm, Tropical
(Ho or Ho Tr) Hot, Very Hot, Infernal