Brown Dwarf: Star or Gas Giant?
- Thread starter Plankowner
- Start date
Peter misses one of the more interesting facts about using the Tidal Forces as a 100D limit. On some red giant stars, the star is so difuse, the 100D limit is inside the star.
And many people assume that when you come out of jump space, it must be at the "100D" limit. So in some systems, you may arrive inside the main star...
And many people assume that when you come out of jump space, it must be at the "100D" limit. So in some systems, you may arrive inside the main star...
Plankowner
SOC-13
Yes, that is why there are Navigational Red Zones.
TheEngineer
SOC-14 1K
Hi !
Using expected suns red giant phase stats the giants atmosphere will extend to a radius of 116 million km.
The typical "tidal" jump limit would move to a radius around 65 million km's, so thats well inside the giant.
Guess, hopefully the navigator knows how to do his job
TE
Using expected suns red giant phase stats the giants atmosphere will extend to a radius of 116 million km.
The typical "tidal" jump limit would move to a radius around 65 million km's, so thats well inside the giant.
Guess, hopefully the navigator knows how to do his job
TE
Plankowner
SOC-13
Giant Stars, White Dwarfs, Neutron Stars and Black Holes will NOT be able to use the "100D" limit. They will have limits that are inside (Giant Stars) or WAY outside the normal 100D limit.
As I stated before, Navigational Red Zones, or blank hexes (not shown on normal maps, because no one can go there anyway...)
As I stated before, Navigational Red Zones, or blank hexes (not shown on normal maps, because no one can go there anyway...)
TheEngineer
SOC-14 1K
Regulary I use an adaption factor of (Density Object/Density Earth)^(1/3).
This could be used to calculate the jump limits for any other-than-earth objects and leads to somehow reasonable results even for giants, though here the jump limit radius is not perfectly correct.
TE
This could be used to calculate the jump limits for any other-than-earth objects and leads to somehow reasonable results even for giants, though here the jump limit radius is not perfectly correct.
TE
Icosahedron
SOC-14 1K
As I see it, The jump limit is just that - a limit. It is not advisable to make a jump within that range, but you can certainly jump anywhere beyond that limit. Navigators would have (or obtain) data on the size of a giant star and could exit jump anywhere within its habitable zone, as this is automatically beyond the tidal jump limit.
If you want to use Peter's figures, you could perhaps 'anchor' the tidal stress like this (assuming I've done my sums right):
Using a standard test body comprising a rigid rod of length 25 metres (experimental TL9 ship length?) arranged radially in a G-field, the tidal force between the ends will be 1 pico-g at a range of about 99 diameters from Earth. This could replace Peter's 'pico-ess' for the tidal model.
The formula I used here is
Delta-a = 2GML/D^3
Where delta a is the acceleration difference between rod ends, G is the gravitational constant, M is the mass of the planet, L is the length of the test body, and D is the distance of the test body from the planet centre.
All in SI units. (I can't be bothered figuring it all out in Traveller units).
If you find I've cocked the maths up, just change the test body length or something, and post a correction.
As I understand it, the tidal force for neutron stars and black holes depends only on the mass. You could approach to within a few thousand km of a 5 solar mass body before the tidal force rivalled atmospheric stresses. I wouldn't like to guess what the radiation levels would be at that distance though!
If you want to use Peter's figures, you could perhaps 'anchor' the tidal stress like this (assuming I've done my sums right):
Using a standard test body comprising a rigid rod of length 25 metres (experimental TL9 ship length?) arranged radially in a G-field, the tidal force between the ends will be 1 pico-g at a range of about 99 diameters from Earth. This could replace Peter's 'pico-ess' for the tidal model.
The formula I used here is
Delta-a = 2GML/D^3
Where delta a is the acceleration difference between rod ends, G is the gravitational constant, M is the mass of the planet, L is the length of the test body, and D is the distance of the test body from the planet centre.
All in SI units. (I can't be bothered figuring it all out in Traveller units).
If you find I've cocked the maths up, just change the test body length or something, and post a correction.
As I understand it, the tidal force for neutron stars and black holes depends only on the mass. You could approach to within a few thousand km of a 5 solar mass body before the tidal force rivalled atmospheric stresses. I wouldn't like to guess what the radiation levels would be at that distance though!
TheEngineer
SOC-14 1K
Hi !
One IMHO intersting implication of using a delta-a value, might be that larger ships have larger jump limits and smaller ships have smaller jump limits, too.
So the jump lim it would not only depend on the masses in the target system but also on the size of the vessels.
E.g. a 25 m ship does well with 12800000 km distance from a earth sized world, but a 100 m ship has to be at 2031000 km to jump safely.
That would be even more significant for central stars jump limits, which would shift from 88 million km for a small 25 ship to 141 million km for a large 100m one.
Is that perhaps an argument for a small ship universe ?
Ico, I actually did not understand the mid sentence in the last paragraph...
Regards,
TE
One IMHO intersting implication of using a delta-a value, might be that larger ships have larger jump limits and smaller ships have smaller jump limits, too.
So the jump lim it would not only depend on the masses in the target system but also on the size of the vessels.
E.g. a 25 m ship does well with 12800000 km distance from a earth sized world, but a 100 m ship has to be at 2031000 km to jump safely.
That would be even more significant for central stars jump limits, which would shift from 88 million km for a small 25 ship to 141 million km for a large 100m one.
Is that perhaps an argument for a small ship universe ?
Ico, I actually did not understand the mid sentence in the last paragraph...
Regards,
TE
Icosahedron
SOC-14 1K
I'm not surprised; I was just messing about with numbers by that stage. I input a stress of 1g for a stellar body of 5Ms and came up with that distance (I think?). I've not done any rigorous checking, the whole thing was just an idea I threw in for the gearheads to play with and the non-gearheads to ignore.
The offshoot of different jump ranges for different size ships is interesting - could have some tactical advantages. It would also make a difference which way the ship was facing...
Maybe the whole idea is too complex. Maybe I should think before I write?
TheEngineer
SOC-14 1K
Ok.
The was a note a few posts ago, that the gravitational force could not be the only aspect for the jump limit extension.
Well Icos though about the ships orientation triggered the idea to use the angular divergence of two g-field vectors as limitation, too.
That would just stress jumpdrives need for a somehow "flat" spacetime environment, meaning very few differences in amount and direction of the gravitational field.
Well, its more complex. Amyway if there would be one easy to use general formula to get the limit, everything would be fine, wouldn't it ?
The was a note a few posts ago, that the gravitational force could not be the only aspect for the jump limit extension.
Well Icos though about the ships orientation triggered the idea to use the angular divergence of two g-field vectors as limitation, too.
That would just stress jumpdrives need for a somehow "flat" spacetime environment, meaning very few differences in amount and direction of the gravitational field.
Well, its more complex. Amyway if there would be one easy to use general formula to get the limit, everything would be fine, wouldn't it ?
