RW Stellar Density

[ShapeShifter]

In the real world of Astronomy, what is the average stellar density for our neighborhood, measured in terms of parsecs (at, say, a maximum radius of 200 pcs)? If I were to base my campaign's map upon some RL estimations would they be denser than the BtB CT sector generation or sparser?

 

[KDLadage]

I think your answer is best found here:

http://www.astronexus.com/hyg

 

[salochin999]

In the real world of Astronomy, what is the average stellar density for our neighborhood, measured in terms of parsecs (at, say, a maximum radius of 200 pcs)? If I were to base my campaign's map upon some RL estimations would they be denser than the BtB CT sector generation or sparser?

http://www.britannica.com/EBchecked/topic/382567/Milky-Way-Galaxy/68086/Density-distribution

If I understand it right (not guaranteed) it's supposed to be about 0.14 stars per parsec near the solar system (so roughly one star per 7 hexes) so a 6 on a d6 would be close.

Getting exponentially more dense the closer you go to the galactic centre - up to multiple stars in one hex.

Looking at travellermap around Terra it looks like they have something close to that.

http://travellermap.com/?x=17.325&y=-106.588&scale=45.2578125

 

[Timerover51]

http://www.britannica.com/EBchecked/topic/382567/Milky-Way-Galaxy/68086/Density-distribution

If I understand it right (not guaranteed) it's supposed to be about 0.14 stars per parsec near the solar system (so roughly one star per 7 hexes) so a 6 on a d6 would be close.

Getting exponentially more dense the closer you go to the galactic centre - up to multiple stars in one hex.

Looking at travellermap around Terra it looks like they have something close to that.

http://travellermap.com/?x=17.325&y=-106.588&scale=45.2578125

That is useful information. Thanks, Salochin999 for finding it, and ShapeShifter for asking the question.

 

[salochin999]

That is useful information. Thanks, Salochin999 for finding it, and ShapeShifter for asking the question.

The bit about multiple stars per hex is interesting - makes you wonder if there are places where STL interstellar travel is viable.

 

[Frankymole]

In the real world of Astronomy, what is the average stellar density for our neighborhood, measured in terms of parsecs (at, say, a maximum radius of 200 pcs)? If I were to base my campaign's map upon some RL estimations would they be denser than the BtB CT sector generation or sparser?

RECONS data says there are 249 systems within 10 parsecs of us (remember, there are more stars than systems due to multiple stellar systems such as binaries, trinaries, or in the case of star systems like Castor, far more!). That means a 5.944% chance of a system in each cubic parsec.

Bear in mind this is in 3D, of course - and some minor brown dwarfs are still invisible to us at presentat larger distances. Closer in (20.5 light years) there are 72 systems, or 88 including brown dwarfs etc that are not quite stars). And 8.46% chance of a system per cubic parsec.

Using a 3D subsector gives more accurate results for jump-3 and above - the standard mapping system in traveller gives far too few systems reachable at the higher jump numbers.

 

[Theophilus]

I was thinking about this just last week, I have a "3d" paper map showing 50 systems withing 16.3 ly of us. I began a search for known or suspected planets in these systems, and was wondering how to create a "traveller map" for known space. Obviously Jump-2 above the ecliptic and Jump-2 below would both be reachable from sol. but not from each other.

 

[Frankymole]

Based on the White Dwarf magazine article for jumps on a 3D map, I did some calculations (I've put the small spreadsheet which shows the jump-numbers required, plus the system presence rolls, on Google Docs/sheets, but they keep changing the share permissions so I don't know how to share it). There's another thread on it somewhere here, anyway!

 

[whulorigan]

Threads on 3D Stellar Mapping

There's another thread on it somewhere here, anyway!

Here are a list of threads:

[FONT=arial,helvetica]3d Star Maps[/FONT]
[FONT=arial,helvetica]Density of Stars Compared to Real Galaxy[/FONT]
[FONT=arial,helvetica]Real Star Map into Traveller Map
[/FONT][FONT=arial,helvetica]My go at a 3D Traveller Sector map
[/FONT][FONT=arial,helvetica]2-D vs 3-D Mapping Experiences
[/FONT][FONT=arial,helvetica]Combining 2D and 3D Mapping
[/FONT][FONT=arial,helvetica]3D Map Form
[/FONT][FONT=arial,helvetica]Stellar densities etc.
[/FONT][FONT=arial,helvetica]Big Imperium - or Traveller 3D
[/FONT][FONT=arial,helvetica]The Solomani Sphere - in 3D [/FONT]

 

[Frankymole]

Interestingly (?) our local stellar neighbourhood - out to 5 parsecs - has 48 systems (plus 4 brown dwarfs), equivalent to a system presence roll of 15+ on 3D6. I've used this as a component of my 3D space system presence rolls (as "sparse" density). The others are:

Rift 18 on 3d6
Deficient 17+ on 3d6
Sparse 16+ on 3d6
Scattered 15+ on 3d6
Standard 14+ on 3d6
Dense 13+ on 3d6
Very Dense (compacted) 12+ on 3d6

A mix of sparse and scattered out to 20.5 ly gives 72 systems, close to the real life figure of about 71.

 

[Frankymole]

I've put my attempt at 3-D mapping our local neighbourhood on the relevant IISS thread: http://www.travellerrpg.com/CotI/Discuss/showpost.php?p=504050&postcount=19