Bakahn the World of Twilight and the system it is in.

[Halcyon]

In several of Mikes’ recent sketches, I mistook a “framing mechanism” to be a large moon, which got me to thinking about the world in which Twilight takes place.

Having searched (quickly) through the forum I have found out that…

a) Much to my surprise, the world is actually called Bakahn, with Anyaral being just one of its continents.
    (Having checked, yes it is in the fluff in the rulebook, but I had totally missed it.)

b) That Bakahn has (at least) two moons, one about our moons size and the second Enar about half it’s size.


Is there any other information about the planet out there ?
I have been assuming that it is roughly similar to Earth in size and climate, but am I correct ?

Also, is there any astronomical (or even astrological) information about the system in which Bakahn resides ?

I recently found my old Traveller RPG books and thought for fun, I might have a go at creating the whole planetary system.
i.e. just a little side project to keep me busy until the miniatures arrive. 

[Carcharoth]

Sorry for the slow response - I've spent the last couple of days travelling (and there's not very good wi-fi on the back of a baruk).
There is a lot of stuff on the forum if you have a search - I assume you found the Twilight ramblings post that pulls a lot of it together?

I have (vague, very long term) plans for other parts of Bakahn (several generations back an Emperor sent out several 'city ships' to explore but they never returned - one crashed and formed what is now Majorn Anis, but the fate of the others is a mystery), but to all intents and purposes Anyaral is the world of Twilight for the moment...

Bakahn just has the two moons (which probably play havoc with the tides but the Fubarnii seem to cope). I think the larger is probably a bit smaller than ours, but certainly equivalent. Enar is smaller and has strange lights on its surface that according to Fubarnii mythology/religion are the fires of the Enarii - heroic Fubarnii who died and were carried on the winds to their new home.

Bakahn itself is very similar to earth - I decided early on to keep that bit of the world consistent with our own rather than tying myself up in knots to adjust things. At a time I had considered setting it on a planet surrounding a gas giant, but that would have just made the seasons even more confusing! Their star is very similar to our own and Bakahn sits comfortably within the Goldilocks zone. I'll admit that the planets have never been detailed or named, so there is lots of room to play there. I imagine there are plenty of Engineers spending their final years carefully tracking those planets...

[Halcyon]

Hi Mike, thanks for the response, at the moment I thought that you might be tied up with other things Kickstarter related, so I was never expecting an immediate response.

I have been trawling though the forum (and the Twilight ramblings), so it is good to have it confirmed that my understanding of your world is correct. In my searches, I also found the old site, which was useful, although the Encyclopaedia does state that Enar is the larger of the two moons! (I am glad that that problem has been resolved).

I agree that making things similar to our world makes life a lot easier, so I have gone with a F8 main sequence star.
This is marginally hotter than our G2 main sequence star, but is similar in size and colour.   
As the habitable/goldilocks zone is further out, Bakahn should be very similar to Earth.

I am still working on the fine details of the worlds and satellites, but what I have come up with for the system so far, working from the star outwards is…

F8 V (main sequence star)
Sekenk,    1 satellite
Ahnufy
Elodin
Dranash,    3 satellites
Bakahn,    2 satellites (habitable/goldilocks zone)
Arlanar,    Large Gas Giant, 5 satellites
Diiwahr,    Large Gas Giant, 2 rings, 6 satellites
Ratharl,    1 satellite
Geprii,    Small Gas Giant, 6 satellites

The Traveller rules only create satellites with a diameter greater than 200km. I don’t think this is a problem, as anything smaller is probably too small to be seen from Bakahn (plus I don’t have to create 50+ satellites for the Gas Giants).

I don’t know if the Enarii actually come from Enar, (I suspect not), but so as not to create a spoiler, I was hoping to give Enar an atmosphere (of some kind), to make it “possible” for the Enarii to live there.
However if it is roughly half the size of our moon, it would be probably be too small to have one.

i.e. In the scheme of things does it matter if Enar has an atmosphere?

Also do you have thoughts on the name of Bakahns’ second moon ?

[Carcharoth]

Looks like a good start to me! I've not played with the Traveller system, but sounds quite clever - it seems to fit with what little I can remember from my degree.
The names also don't seem out of place, so well done with that.

Enar wouldn't be big enough for a proper atmosphere, unless there's something else going on (but I'm not telling if that is the case). In the scheme of things it doesn't matter though.

I can't remember if the second moon has been named. I think it has been, but possibly only in hand written notes somewhere. I think it's fair game to rename it for completeness.

[Kryptovidicus]

More stuff for in the updated rule-sourcebook .
Just kidding (a bit a least)!

[Halcyon]

More stuff for in the updated rule-sourcebook .
Just kidding (a bit a least)!

Eek !!! I better get it finished sharpish then ! lol 

Progress update
The planet and satellite sizes have been created.
The orbital periods for the Planets have been worked out.
The satellites have all been named (thanks to the random name generator I created).

I just need to find some time to sit down and work out the orbital periods of the Satellites. 


 

[Halcyon]

Phew ! I have finally finished creating the solar sytem Bakahn is in.

I just hope that I got all the calculations right and that it is of some use.

In any case I had fun doing it.  

Orbit  Name       Mean Radius  Atmosphere       Hydrographics  Orbital Period

Sun    F8 V
0      Sekenk      1,640.2 km  None             None             30.46 days
   39  Bretom        127.9 km  None             None             23.67 hours

1      Ahnufy      3,402.7 km  Very thin        None             86.17 days

2      Elodin      3,390.8 km  Very thin        None            178.49 days

3      Dranash     4,922.2 km  Thin             None            315.37 days
   12  Brenet      2,441.7 km  Very thin        None              3.39 hours
   42  Enbahr      3,637.9 km  None             None              5.42 days
   46  Greshenk    2,710.7 km  None             None              7.80 days

*4     Bakahn      6,417.6 km  Standard         71% water       534.25 days
   49  Enar          829.4 km  None             None             15.13 days
   58  Kajor       1,637.8 km  Trace            None             24.91 days
            
5      Arlanar    60,517.4 km  Large Gas Giant                    4.37 years
    7  Eloip       2,436.6 km  None             None              3.79 days
    9  Eloish      2,309.0 km  None             None              8.07 days
   11  Kithenk       223.7 km  None             None             14.73 days
   40  Menet       3,340.6 km  Trace            None            707.72 days
   47  Dranar      4,019.3 km  Very thin        12% water         3.14 years
            
6      Diiwahr    67,448.6 km  Large Gas Giant                   11.06 years
    1  Ring System     n/a     None             None               n/a  
    3  Ring System     n/a     None             None               n/a  
    8  Jenor       2,226.3 km  Very thin        None              4.83 days
   13  Dralin        295.6 km  None             None             20.71 days
   29  Enmir       2,446.2 km  None             None            229.84 days
   36  Breim       2,505.4 km  None             1% water        439.69 days
   62  Grenul      1,615.5 km  None             None              6.15 years
  156  Dravramar   4,588.9 km  None             None             97.89 years

7      Ratharl     4,011.3 km  None             33% water        29.49 years
    9  Tamahr        343.7 km  None             None              1.11 hours

8      Geprii     34,754.5 km  Small Gas Giant                   80.92 years
    5  Enosh       2,026.5 km  None             None             10.09 hours
    6  Bregahn     3,409.8 km  Thin             4% water         17.41 hours
    8  Yolin       3,930.8 km  None             2% water         41.23 hours
   12  Berad       1,226.5 km  None             None              5.81 days
   13  Zhenar        242.9 km  None             None              7.39 days
   30  Pitom       4,927.2 km  Very thin        None             90.32 days

Notes:
Bakahn is in the habitable/goldilocks zone and is very like Earth.
Satellite orbit distances are in radii of the central planet.
Trace atmospheres have a pressure less than 0.1 atmospheres.
Very thin atmospheres have a pressure of 0.1 to 0.42 atmospheres.
Thin atmospheres have a pressure of 0.43 to 0.70 atmospheres.
Standard atmospheres have a pressure of 0.71 to 1.49 atmospheres.


EDIT: Orbital Periods for Bakahn, Dranash and Elodin changed.

[Carcharoth]

Good levels of detail there!
How come bakahn has such a long year? I had been working on a year of around 360 days
A longer year would have interesting consequences - fubarnii only live for around 20-25 years, so one year on backhand would be equivalent to about 4 'human years'.

[Halcyon]

How come bakahn has such a long year?

It is all down to...
a. the solar mass of the star
b. the distance of the planet from the star

Also Bakahn had to be in the habitable zone.

Bakahn has a F8 V star, so it's habitable zone is in orbit 4.
Earth has a G2 V star, so our habitable zone is in orbit 3.
(i.e. Mars is in orbit 4 and has a 687 day year.)

I did however just use Travellers default orbital distances  (based on our solar system).

Having done some more number crunching, I have now worked out a more exact habitable zone distance.

Bakahn has now moved from being 1.6 AU to just 1.35 AU from the star.
Consequently it now has an orbital period of 534.25 days.
( That is about one and half times our year and a much better fraction for working out leap years.)  

I don't see any point in changing the default distances for the other planets so will leave them as is.


EDIT: Changed my mind and moved Dranash and Elodin closer to the Sun by 0.05 AU.