of Interstellar Exploration and the Development of *Cultures
(UNDER
CONSTRUCTION)
of Interstellar Exploration and the Development of *Cultures
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| For
other realistic takes on a 'near term' Stellar Expansion, D/M's are
directed to SPI's "Universe", Tri-Tac's
"FTL: 2448" and Game Designer's Workshop's "Traveller: 2300" and their
incomprehensible star charts. |
|
| After
the Centauri Combine proved it was possible and very definitely
worthwhile, a whole flotilla of expeditions headed spinward (roughly
four
hours either side
of R.A. 0). After all where else could they go? The semi-mythical
Innes' Star? |
 Red Dwarfs andTwilight WorldsA favorite of Science Fiction since the days when even Mercury could have been a habitable planet! The search for Habistars has, until quite recently, naturally focussed on stars with a similar nature to that of Sol. And included the dimmer F-types and the brighter K-types as suggested by Dole. However recent models indicate that close orbiting planets of Red Dwarfs are also prime candidates for habitability, nominally under the 'wet' water criterion, previous models suggested that such a planet would need to be so close to its M-type primary that the body would rapidly become tidally locked; with one hemisphere: Dayside, permanently facing the primary and the other: Nightside, in its permanent shadow. (Just like modern ETI Searchers, Science Fiction authors did not like to complicate things by adding another sun to the mix.) Multiple star systems aside; the original theory behind such a world required a tidally locked body with a limited libration 'wobble' to provide seasons. With a good reserve of water, a 'twilight zone' of habitability could be maintained over many millions of years; wrapped longitudinally through the poles. To stop the water and, eventually, the atmosphere, from freezing out on the Nightside a 'sufficiently' dense atmosphere was required. Circulating from Nightside to Dayside at ground level and from Dayside to Nightside via the stratosphere; thus evening out the temperatures of the sub-solar point (Dayside) and the ante-solar point (Nightside). Thus water, melting from the Nightside Glaciers would drain through taiga, cool temperate forests,... into a longitudinal world river or ocean. The sunward swamp shores would become jungle, then grassland and finally desert. Beyond the Twlight Zone, the Dayside temperatures would naturally increase to the sub-solar point; which would traditionally have to have a temperature "hot enough to melt lead!" All very Romantic... All very wrong... Modern computer models have shown that a 'sufficiently' dense atmosphere is not required! Indeed a 'Twilight World' gets to keep its atmosphere from freezing out on the Nightside at pressures down to 0.15 bar. So provided the world is sufficiently Earthlike with a (Dole derived) Mass of 0.4MT and a density to go with it ~ 5gm/cc (iron core, silicate mantle) the gravity alone will retain a decent atmosphere. without the need for constant vulcanism or exotic (heavy) atmospheric constituents liike neon, argon or hydrogen sulphide! Such a world would also need water (obviously!) and contiguous deep water at that. Kept wet under the ice covered Nightside ocean basin. Deep cold currents would circulate the world's oceans, just like those on Earth. But, instead of flowing from the poles to the equator and back again; these would circulate in parallel with the atmospheric currents. Dayside to Nightside: Nightside to Dayside. In both cases the terrain: mountain ranges, continental shelves, rift valleys and other such crustal fripperies would affect the local climate. Conversely the 'lead smelters of Dayside' would find themselves under the cloud cover of a permanent hurricane. The sub-solar point generating an anti-cyclone of continental proportions. The result: the 'twilight zone' is shifted towards Dayside by a considerable margin until the wind and rain of the sub-solar hurricane become problematic. Thus any reasonably dense, reasonably sized, world with a reasonable gravitational well - will do just fine; even if it is tidally locked within a gnats whisker of a Mercurian orbit: typically 0.3 A.U./ 50 day year with an eccentricity approaching 0.0. The only contention left is the nature of the M-type star itself; most of which are Flare Stars: erupting on a regular basis. Whilst a reasonably dense atmosphere and, importantly, a decent magnetosphere (generated by a molten iron core) will go some way to protecting the colonists; underground storm shelters and decent headgear will never be too far away. Thus those primaries: K5 to M2 ...relegated to the 'also ran' candidates for Habitability by Doleet al are now prime targets. If nothing else their longevity on the Main Sequence makes them long term investments in the Interstellar Real Estate business. For that reason these Worlds, so long relegated to the Twilight, are now prime candidates for the discovery of extraterrestrial life! |
| Habistars: Sol Types and brighter Named Stars within 50 ly | |||
Verify data independantly |
Distance from Sol |
Type |
Companions (And
Comments) |
| AlphaCent | 4.48 |
G2 V |
B: K0; C: M (Hub World. See above.) |
| Procyon A/B (Alpha Canis Minoris) |
11.40 ly | A:F5V-IV B: DA VII |
Separation 15.8 A.U. Period 40.6 years; Mass A:
1.8 MSol, Mass B: 0.6 MSol Homeworld Daou (PseudoDracoCentauroid Procyonencis sapiens) |
| Tau Ceti | 11.88 lytes |
G8 V |
(Hub World) |
| Van Maanen's Star | 13.62 |
G1 VII |
Sub Dwarf |
| Delta Pavonis | 18.68 |
G8 V |
(Hub World) |
| Sigma Draconis 'Smaug' | (18.48 lytes) | [K0] V | 'Hespera' (Smaug II) |
| Eta Cassiopiae A | 19.06 |
G0 V |
B: M0 V (Hub World) |
| 82 Eridani | 20.22 |
G5 V |
(Hub World) |
| Beta Hydri | 20.58 |
G1 IV |
(Hub World) |
| Xi Bootis A | 22.02 |
G8 V |
B: M0 V; C: K4 V Companions: no stable
T-type orbit |
| Zeta Tucanae | 23.32 |
G2 V |
(Hub World) |
| 1: AC +48 1595 -89 | 23.59 |
GO V |
(Core World. See below) |
| 2: DM -46 11370 A | 24.93 |
G8 V |
B: MO V (Core World) |
| Mu Cassiopeiae A | 25.01 |
G5 VI |
B: M8 V (Hub World) |
| Mu Herculis A | 26.35 |
G5 IV |
B, C: M4 V Sub Giant + Companions: no stable T-type orbit |
| 3: Beta Coma Berenices | 27.2 |
G0 V |
(Core World) |
| 4: DM -17 3813 | 27.47 |
G6 V |
(Core World) |
| 5: Alpha Mensae | 28.38 (33.1) |
G5 V |
(Core World) |
| ?????????? | 28.8 |
G8 VI |
Gliese 4510.0 The Flying Star' 2300:'Henry's Star' Sub Dwarf |
| 6: 61 Ursae Majoris | 29.65 |
G8 V |
(Core World) |
| 7: DM +36 1979 | 29.83 |
G8 IV |
B: MO V Sub Giant |
| Beta Canis Venaticorum 'Chara' |
29.91 (29.85) |
G0 V |
Homeworld |
| Xi Ursae Majoris A/B | 29.92 |
both G0 V |
C: M0 V Infinity Loop World see
XX on World Generation Table |
| beta Shell subSecrot marker Stars |
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| 58 Eridani |
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| HD 10307 |
~42 |
Companion Star what type |
|
| HD 211415 |
~42 + |
half the metal content of Sol
cooler |
|
| 18 Scorpi |
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| Psi Serpentis ? Lambda Serpens |
11 pc |
G0 |
|
| 51 Pegasi |
50.11 |
Jovian planet with one week period orbital
distance ~4 million miles ~ 4 day year? |
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VIII/ AC +48 1595 -89 23.59ly GO V IX/ DM -46 11370 A 24.93ly G8 V B: MO V X/ Beta Coma Berenices 27.2ly G0 V XI/ DM -17 3813 27.47ly G6 V XIII/ 61 Ursae Majoris 29.65ly G8 V DM +36 1979 29.83ly G8 IV B: MO V Sub Giant |
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