Before I reinvent the wheel, has anyone done a chart of stellar radii such that jump shadows and travel times could be calculated? All I have to go by is the small section in CT book 6 with lots of interpolation to be done.
Stellar Radii
- Thread starter Spartan159
- Start date
Such a chart is subject to interpolation in every version I've seen.
Yes. I'll be damned if I can remember where I last saw such a beast then.
I remember someone even set up a mini program that calculated it. Very nifty bit of coding.
Go questing or Googling, young Pellinore. Will post if it comes to me.
Shalom,
Maksim-Smelchak.
Damn'd little fewmets I can find what? One would think I was after the questing beast. I did happen upon this beast though... http://astro.unl.edu/classaction/animations/stellarprops/stellarlum.html
GT First In (page 53sb) contains the following formula:
309,000 x square root of (L / T ^ 2) where
L is the luminosity of the star (as provided by the tables)
T is the temperature in Kelvin (also provided by the tables)
The result is diameter in AU.
GT First in page 50,51 have tables for the type, luminosity and temperature of stars. It recommends interpolation to find exact values, and introduces a random factor to match the real world. Stars of the same type can vary in luminosity by 30% or more.
309,000 x square root of (L / T ^ 2) where
L is the luminosity of the star (as provided by the tables)
T is the temperature in Kelvin (also provided by the tables)
The result is diameter in AU.
GT First in page 50,51 have tables for the type, luminosity and temperature of stars. It recommends interpolation to find exact values, and introduces a random factor to match the real world. Stars of the same type can vary in luminosity by 30% or more.
Thanks for that heads up, I will look at that ASAP. Meanwhile I had found this old post:
Using information in CT Book 6 Scouts I came up with some very different answers:
Old Data Main Star Radii Jump Shadow km Habitable Zone km Difference km travel time sec DD:HH:MM:SS
0723 Trifuge 66:07:30:02 F0 V 1.7 236538000 418900000 -182362000 Not in shadow
1803 Menorb 66:07:30:02 K2 V 0.7712 107304768 104700000 2604768 32279 00:08:57:59
1924 Ianic 66:07:30:02 M3 V 0.4344 60442416 29900000 30542416 110530 1:06:42:10
2232 Crout 66:07:30:02 M7 III 294 40907160000 5804000000 35103160000 3747167 43:08:52:47
1216 Stellatio 46:21:21:39 M3 V 0.4344 60442416 29900000 30542416 110530 1:06:42:10
1402 Farreach 46:21:21:39 M3 III 162 22540680000 2932000000 19608680000 2800620 32:09:57:00
1102 Riverland 33:03:45:01 M2 V 0.4726 65757564 29900000 35857564 119762 1:09:16:02
1131 Faldor 33:03:45:01 M2 V 0.4726 65757564 29900000 35857564 119762 1:09:16:02
1204 Mongo 33:03:45:01 M6 III 261 36315540000 5804000000 30511540000 3493511 40:10:25:11
1212 Digitis 33:03:45:01 M3 V 0.4344 60442416 29900000 30542416 110530 1:06:42:10
1529 Steel 33:03:45:01 K8 V 0.5558 77334012 29900000 47434012 137745 1:14:15:45
2933 Raydrad 33:03:45:01 M7 III 294 40907160000 5804000000 35103160000 3747167 43:08:52:47
2935 Murchison 33:03:45:01 M5 III 228 31723920000 5804000000 25919920000 3219933 37:06:25:33
0927 Narsil 30:16:43:18 G6 IV 2.9 403506000 418900000 -15394000 Not in shadow
2419 Cogri 30:16:43:18 M1 V 0.5108 71072712 29900000 41172712 128332 1:11:38:52
1337 Judice 21:16:56:27 M3 V 0.4344 60442416 29900000 30542416 110530 1:06:42:10
1733 Lydia 21:16:56:27 M4 III 195 27132300000 2932000000 24200300000 3111289 36:00:14:49
2134 Caledonia 21:16:56:27 M4 III 195 27132300000 2932000000 24200300000 3111289 36:00:14:49
2411 Keanou 21:16:56:27 M3 III 162 22540680000 2932000000 19608680000 2800620 32:09:57:00
2936 Hammermium 21:16:56:27 M3 V 0.4344 60442416 29900000 30542416 110530 1:06:42:10
1909 Hefry 17:17:20:47 K6 II 146.6 20397924000 5804000000 14593924000 2416106 27:23:08:26
2402 Heya 15:08:21:39 K6 III 46.2 6428268000 2932000000 3496268000 1182585 13:16:29:45
0115 Xhosa 12:12:45:55 M0 V 0.549 76387860 29900000 46487860 136364 1:13:52:44
1116 Frenzie 12:12:45:55 M3 III 162 22540680000 2932000000 19608680000 2800620 32:09:57:00
1934 Weiss 12:12:45:55 M1 V 0.5108 71072712 29900000 41172712 128332 1:11:38:52
2701 Lablon 12:12:45:55 M2 III 129 17949060000 2932000000 15017060000 2450882 28:08:48:02
2940 Thornnastor 12:12:45:55 M1 V 0.5108 71072712 29900000 41172712 128332 1:11:38:52
3021 Brodie 12:12:45:55 M1 III 96 13357440000 2932000000 10425440000 2042101 23:15:15:01
3114 Huderu 12:12:45:55 M0 V 0.549 76387860 29900000 46487860 136364 1:13:52:44
0101 Zeycude 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
0129 Uniqua 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
0421 Zamine 1:06:41:48 M3 V 0.4344 60442416 29900000 30542416 110530 1:06:42:10
0518 Faisal 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
0710 Stave 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
1018 Choleosti 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
1138 Tarsus 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
1515 Calit 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
1739 Aster 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
1935 Windsor 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
2036 Glisten 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
2309 Yurst 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
2406 Moughas 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
2415 Vreibefger 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
2418 Icetina 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
2720 Loneseda 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
3004 Zykoca 1:06:41:48 K9 V 0.5524 76860936 29900000 46487860 136364 1:13:52:44
3008 Pysadi 1:06:41:48 F9 V 1.104 153610560 239300000 -85689440 Not in shadow
3035 Prilissa 1:06:41:48 K4 V 0.6344 88270416 104700000 -16429584 Not in shadow
Radii interpolated from chart on p.45 Travel time calaculated as t = 2*SQRT(d/a) where t= sec, d= distance in meters, a= 10m/sec aka 1G
I am sure I made mistakes somewhere.
The original numbers Cryton quoted are mine. I generated them for Don as part of the T5SS discussions. I remember Cryton asking off board for a copy of the spreadsheet I used, which is why it doesn't appear on any other messages other than Cryton's original quote in the Reference section.
Not sure what data was used...the stellar data was in flux at the time and we were looking at all the published data/info on each system in the Spinward Marches and trying to reconcile it all and come up with the data of best fit...often there were multiple conflicting sources. The spreadsheet I used to generate these numbers has moved on with more up to date data.
Sometimes changing the stellar data was the best fit for what had been published, especially if an author had failed to mention the stellar jump masking, or an adventure hinged on being able to jump at 100D from the mainworld and that wasn't possible with the given star.
fridge
Not sure what data was used...the stellar data was in flux at the time and we were looking at all the published data/info on each system in the Spinward Marches and trying to reconcile it all and come up with the data of best fit...often there were multiple conflicting sources. The spreadsheet I used to generate these numbers has moved on with more up to date data.
Sometimes changing the stellar data was the best fit for what had been published, especially if an author had failed to mention the stellar jump masking, or an adventure hinged on being able to jump at 100D from the mainworld and that wasn't possible with the given star.
fridge
Enoki
SOC-14 1K
Here's the table of Stellar radii from CT Book 6 in 100 diameter AU:
.................Ia.........Ib...........II...........III..........IV...........V..........VI
B0..........48.60 28.04..... 20.56..... 14.95..... 12.15..... 9.35
B5..........70.09 32.71..... 18.69..... 9.35....... 4.95....... 4.11
A0..........126.17....46.73..... 16.82..... 5.79....... 4.21....... 2.99
A5..........139.25....51.40..... 13.08..... 4.30....... 2.52....... 1.68
F0..........162.62....55.14..... 14.95..... 4.39....... 2.52....... 1.59
F5..........190.65....56.07..... 16.82..... 4.86....... 2.43....... 1.31....... 1.07
G0..........278.50....78.50.... 23.36..... 6.64....... 2.34....... 0.96....... 0.95
G5..........424.30....119.63... 34.58..... 10.28......2.62.......0.85....... 0.51
K0..........611.21....201.87... 50.47......14.95..... 3.08....... 0.85....... 0.37
K5..........943.93....366.36... 115.89....39.25...................0.53....... 0.29
M0..........1371.03..800.93... 221.50... 58.88................... 0.51....... 0.24
M5..........2822.43..1937.38..665.42... 213.08................. 0.33....... 0.10
M9..........3270.09..2687.85..870.09... 336.45................. 0.19....... 0.05
Orbit AU
0 0.2
1 0.4
2 0.7
3 1
4 1.6
5 2.8
6 5.2
7 10
8 19.6
9 38.8
10 77.2
11 154
12 307.4
13 614.8
14 1229.2
15 2458
.................Ia.........Ib...........II...........III..........IV...........V..........VI
B0..........48.60 28.04..... 20.56..... 14.95..... 12.15..... 9.35
B5..........70.09 32.71..... 18.69..... 9.35....... 4.95....... 4.11
A0..........126.17....46.73..... 16.82..... 5.79....... 4.21....... 2.99
A5..........139.25....51.40..... 13.08..... 4.30....... 2.52....... 1.68
F0..........162.62....55.14..... 14.95..... 4.39....... 2.52....... 1.59
F5..........190.65....56.07..... 16.82..... 4.86....... 2.43....... 1.31....... 1.07
G0..........278.50....78.50.... 23.36..... 6.64....... 2.34....... 0.96....... 0.95
G5..........424.30....119.63... 34.58..... 10.28......2.62.......0.85....... 0.51
K0..........611.21....201.87... 50.47......14.95..... 3.08....... 0.85....... 0.37
K5..........943.93....366.36... 115.89....39.25...................0.53....... 0.29
M0..........1371.03..800.93... 221.50... 58.88................... 0.51....... 0.24
M5..........2822.43..1937.38..665.42... 213.08................. 0.33....... 0.10
M9..........3270.09..2687.85..870.09... 336.45................. 0.19....... 0.05
Orbit AU
0 0.2
1 0.4
2 0.7
3 1
4 1.6
5 2.8
6 5.2
7 10
8 19.6
9 38.8
10 77.2
11 154
12 307.4
13 614.8
14 1229.2
15 2458
Theophilus
SOC-13
Maybe I'm misunderstanding the question. Sol's radii places it's jump shadow well past Earth's orbit, almost 3/4 of the way to Mar's.
Any ship jumping into the Sol system exits jump space closer to Mar's than Earth, so Mar's should logically be a shipping hub and transfer point, since cargo must be transported to Earth.
Sol is not a giant star, so it should come into play.
Enoki
SOC-14 1K
That's not how the rules have it. You have to be 100 diameters beyond a gravity source like a planet or whatever to jump. That's how the rules have it. The Earth is 107 diameters (give or take a little bit) beyond the sun at 1 AU. Therefore, by the rules the Earth is outside Sol's jump shadow.
Timerover51
SOC-14 5K
How does this work for Regina then? It is orbiting a large Gas Giant, which in turn is orbiting an F7 star, with 2 other stars in the system?
Does the presence on its course of a large gravity well snap a ship out of Jump Drive?
FWIW the Regina system is detailed in book 6 pg 55. A trinary system, the primary is Lusor, an F7 V with Speck, a DM in close orbit. Regina orbits the Large GG Assiniboia in orbit 4, 1.6 AU out. The third star, Darida, an M6 V, is in far orbit at 5,000 AU.
As to the gravity well, that's another :CoW: According to T5, coming within 100 diameters of anything will precipitate a ship out of Jump if I understand correctly.
And just for interest, Wikipedia has the sun's radius as 0.00465047 AU, multiplying by 200 gets 0.930094 AU, inside Earth's orbit.
I interpolate Lusor as having a radii of 1.252, so Lusor's Jump Shadow comes out at 1.164477688 AU, just outside the orbit of Assiniboia/Regina. Next question would be just how large is Assiniboia? T5 lists Large GG as being 50,000mi to 250,000mi diameters. Worst case scenario, 250,000mi = 0.00268945004 AU, x100 = 0.268945004 AU, + 1.6 AU orbit = 1.868945004, so insult to injury. 1G you say?
Enoki
SOC-14 1K
I'd have to look up the stuff on Regina as I use the other side of the Empire almost exclusively and only rarely deal with the Spinward Marches. But the above looks right.
With gas giants, I simply roll out their diameter and note it when doing the system up: LGG, 55,000 mi (radius). Gas giants almost always overshadow all their satellites for the 100D gravity well rule. So, you use the gas giant to determine where the FTL event horizon, as I put it.
Usually this works out to something like 15+ hours at 1G to cover the distance, a drawback to using gas giants to refuel. It also makes gas giants attractive to pirates as it gives such ships lots of time to take on a possible prize.
I must be doing something wrong. I googled 0.268945004 AU to m and got 40233599933.803. SQRT (40233599933.803m * 10m/sec) = 634299.61322550875413284053336594 sec. This nifty page says 634300 sec = 7 days 08:11:40
Timerover51
SOC-14 5K
That is where I got the data on the Regina system.
So basically, a Jump Drive is the same in that respect as the Quantum 1 Drive in Larry Niven's Known Space series. Would that include comets as well? How well a star system's Oort Cloud mapped, and what are the chances of getting through it?
Hmm, a large Gas Giant within just 1.6 AU of an F7 star. As a large Gas Giant, Regina is very likely to be tidally locked to it. I would have to do some digging, but if I remember correctly a tidally locked body is not going to have a magnetic field. How fast is Regina orbiting its Gas Giant?
Similar threads
