Stellar densities etc.

[ffilz]

Let's say I'm going to create a "universe" in 3-D, and rather than trying to use hexes, I am just going to use XYZ coordinates.

I want to have Sol/Earth be part of my universe, and would like to use real star data. I've found some various sources to start from (the map from SPI's Universe, SolStation.com, and one or two others). But that is likely missing stars, especially dimmer stars as one gets farther away from Sol.

Does anyone have any thoughts as to how to fill in those "missing" stars? My initial thought is to do everything within at most 100 LY, perhaps smaller.

The next step will be to generate planetary systems for the stars. I'm inclined to use a mix of "realistic" random generation, combined with just placing things because I want something there. Of course I should account for anything known.

What is the best guess as to what star types could even support earth-like planets? What is current thought on what types of stars would not have any planets at all?

Thanks

Frank

 

[Tellon]

just google for info -- astronomical data on nearby stars is easily found

I found this like in just a few seconds: (going over the 50 nearest stars)
http://www.cosmobrain.com/cosmobrain/res/nearstar.html

Here are the 50 "brightest stars we see with our eyes)
http://www.cosmobrain.com/cosmobrain/res/brightstar.html

Here is a 3D image of some of the nearby stars in regards to SOl ..
http://upload.wikimedia.org/wikiped....svg/600px-Nearby_Stars_(14ly_Radius).svg.png

 

[ffilz]

SolStation.com seems to have quite a bit of data, the big question though is at what distance does it become likely we have missed stars? Ad what types, how far away for example would we expect to have found all the brown dwarfs?

 

[Tellon]

SolStation.com seems to have quite a bit of data, the big question though is at what distance does it become likely we have missed stars? Ad what types, how far away for example would we expect to have found all the brown dwarfs?

It depends on Brown Dwarves .. I figure we could have a BD floating in the Oort belt and we wouldn't know it. Since BD's are about 1.1+ Jup dia -- so not that big, we'd have to find them generally via IR as their visual signature would be way too faint for most to be seen --
so we're finding them as we go along -- since M type stars are very plentiful -- we easily expect BD's to be plentiful too .. so what we could expect to be a heavy mass GG around a star could be a BD in disguise

 

[Whipsnade]

Frank,

There's a poster on the Mongoose Traveller forum named Constantine Thomas and/or Doctor Evil Ganymede. He's an actual doctor of planetology and would be the best person to answer your questions.

In fact, he may still have materials up on his personal website which answer your questions.


Regards,
Bill

 

[E.D.Quibell]

Frank,

There's a poster on the Mongoose Traveller forum named Constantine Thomas and/or Doctor Evil Ganymede. He's an actual doctor of planetology and would be the best person to answer your questions.

In fact, he may still have materials up on his personal website which answer your questions.


Regards,
Bill

You can catch him on the SFRPG boads, as well as those dedicated to planetology (of which I have no knowledge).

Regards,

Ewan

 

[coliver988]

Frank,

There's a poster on the Mongoose Traveller forum named Constantine Thomas and/or Doctor Evil Ganymede. He's an actual doctor of planetology and would be the best person to answer your questions.

In fact, he may still have materials up on his personal website which answer your questions.


Regards,
Bill

I think EDG was banned from Mongoose, just as he got banned here. Really good information, but far too inflexible (I have a PhD - anything I say is the absolute truth was the general tone you got, but he did know his stuff. Too bad a lot of the science keeps changing as we discover more things that don't fit the traditional models)

 

[Whipsnade]

I think EDG was banned from Mongoose, just as he got banned here.

Coliver,

Drat.

Really good information, but far too inflexible...

That's good thumbnail description of the man. His social skills are... somewhat lacking is the best way to put it.

(I have a PhD - anything I say is the absolute truth...

Sadly true. He also thought his PhD meant he was fully knowledgeable of topics well beyond his field of study, not an uncommon failing.

... but he did know his stuff.

Which is why he was so useful. Several years ago on the JTAS boards I "watched" him quickly and effortlessly put together a plausible model to explain Antares' canonical UWP. He followed that up with a description of a supernova in Traveller terms. Let's just say my jaw dropped.

I'm an utterly shameless idea thief. I'll use anybody and anything no matter how "prickly". For me, EDG's "game" was worth his "candle". For too many others sadly, it was not.


Regards,
Bill

 

[aramis]

I think EDG was banned from Mongoose, just as he got banned here. Really good information, but far too inflexible (I have a PhD - anything I say is the absolute truth was the general tone you got, but he did know his stuff. Too bad a lot of the science keeps changing as we discover more things that don't fit the traditional models)

No, he ASKED to be banned from here.

 

[Gray Lensman]

http://evildrganymede.net/rpg/rpg_f.htm is his worldbuilding hub

 

[Tellon]

http://evildrganymede.net/rpg/rpg_f.htm is his worldbuilding hub

His article on brown dwarves and super-jovians is good -- which is why I use it. It makes people with low G fuelers think twice about what GG's they head to -- so SGG's become much more popular due

I dont think I have his stuff on super earths -- basically size A worlds with enough mass to have a thick atmosphere and plausability to be water worlds -- but enough scientific papers are written on them, one can do research fairly easily.

The favorite part of his worldbuilding section was the starmap of +6 and -6 psc layers above and below Sol -- so with 13 layers, he gives a good look of what stars are nearby -- so it makes a really superb 3D map look (using traveller hexes)

 

[Peter Schutze]

>at what distance does it become likely we have missed stars?

For M and smaller several astronomers have claimed that they can't be sure theres nothing closer than Proxima centauri

>Ad what types, how far away for example would we expect to have found all the brown dwarfs?

about the orbit of pluto, seriously !

We are finding stars in the M range within 20LY quite regularly. RECONS has found at least a dozen since the first of their papers I read in 2006 of which teegardens is the best known (ie it has a wikipedia entry)

>Since BD's are about 1.1+ Jup dia

Was going to correct this before I realised you were referring to (fairly irrelavant for detection AFAIK) diameter rather than mass .... Brown dwarfs are usually in the >4 Mj (mass of Jupiter) range.

One of the big things that surprised me is that stars can have quite a range of Mass for a given class eg G2V like Sol

 

[Frankymole]

>Since BD's are about 1.1+ Jup dia

Was going to correct this before I realised you were referring to (fairly irrelavant for detection AFAIK) diameter rather than mass .... Brown dwarfs are usually in the >4 Mj (mass of Jupiter) range.

One of the big things that surprised me is that stars can have quite a range of Mass for a given class eg G2V like Sol

Sorry for the thread necromancy, but the latest WISE data indicates that brown dwarfs should be defined as about 13 Mj (i.e. thirteen Jupiter masses) or more and capable of fusing Deuterium.

WISE 0855−0714 for instance is more likely to be a rogue planet: a gas giant of 3-10 Jupiter masses.