Planet Builder 1.0

[selden]

Ras',

I was enjoying flipping through the planet textures and came across a couple with really strange features. In particular, gc_earth_04-clouds.png has this gigantic pitch black hole that's sort of the shape of Australia. Is that a glitch or on purpose?

gc_gasgt_04-clouds.png as a rectangluar white mark. I'm sure that's a glitch.

[Rassilon]

It came with the clouds...The clouds came from xplanet when it was still around...the clouds always seem to have a faint image of the continents there...I dont pay much notice to them I suppose...

gc_gasgt_04-clouds.png as a rectangluar white mark. I'm sure that's a glitch.

Not on mine...Might be a bad download...if the download didnt take long grab it again...must of been like the generator_b download...reset by peer or another wonderful error

[Brons]

Since my program, StarGen, has been mentioned here a couple of times using different URL's, I thought I'd post the official one. (Sadly, due to the actions of my original ISP it has changed a couple of times in the past few months, but with a new ISP and an assist from ZoneEdit, it is back where it belongs and will hopefully stay stable. Sorry for the inconvenience.)

StarGen's web page can be found at http://www.eldacur.com/~brons/NerdCorner/StarGen/StarGen.html.

StarGen is a random solar system generator based on the accretion disk model work first done about 3 dozen years ago at Rand by Stephen Dole. As another poster has pointed out, the model is obsolete, but it does create plausible looking solar systems. Since becoming a fan of Celestia a few months back, I've been working on adding support for creating .ssc files using it. That work is incomplete, but progressing.

Comments on StarGen are always appreciated.

Thanks,
Brons

[Rassilon]

Since my program, StarGen, has been mentioned here a couple of times using different URL's, I thought I'd post the official one. (Sadly, due to the actions of my original ISP it has changed a couple of times in the past few months, but with a new ISP and an assist from ZoneEdit, it is back where it belongs and will hopefully stay stable. Sorry for the inconvenience.)

StarGen's web page can be found at http://www.eldacur.com/~brons/NerdCorner/StarGen/StarGen.html.

StarGen is a random solar system generator based on the accretion disk model work first done about 3 dozen years ago at Rand by Stephen Dole. As another poster has pointed out, the model is obsolete, but it does create plausible looking solar systems. Since becoming a fan of Celestia a few months back, I've been working on adding support for creating .ssc files using it. That work is incomplete, but progressing.

Comments on StarGen are always appreciated.

Thanks,
Brons

If you want maybe look into writing something like this for Celestia....

[selden]

Ras',

Brons did write that he's planning to have it create .SSC files...

What I've been wondering (I haven't looked at the source yet) is how hard it would be to have it produce intermediate results. In other words, show a system at several stages of evolution between the initial accretion nebula and the "final" stable system. Could it produce orbiting swarms of the intermediate planetesimals, for example?

[Rassilon]

Ahh missed that part...

[Brons]

selden wrote:

What I've been wondering (I haven't looked at the source yet) is how hard it would be to have it produce intermediate results. In other words, show a system at several stages of evolution between the initial accretion nebula and the "final" stable system. Could it produce orbiting swarms of the intermediate planetesimals, for example?

I doubt that it could be done in an interesting at present. It throws in a single planetesimal at a time, acreting it all the way up to full-sized planet before tossing in the next. Then, once it's gotten all the planets it's done. If two planets get too close to each other, they merge.

The main reason that the model doesn't match most of the actual extra-solar systems is that it doesn't put really big gas giants as close to the primary as the earliest systems. One thought on this is that these planets might form further out and then get pulled out of their original orbits by interactions with other planets.

Back a couple or three decades ago when the model in StarGen originated, planets knocking each other around sounded to much like Immanuel Velikovsky, and not at all respectable.

I've been thinking of trying to jazz the model up a bit, making it handle the placement of known planets, simulating planets form in one orbit but moving to another. If I do that, perhaps I could make it a bit less sequential, which might allow it to make the sort of intermediary systems you're asking about.

Unfortunately, I've been short on hacking time lately.

Brons

[selden]

Brons,

Thanks for thinking about it. It does seem that the formation of planetary systems can be a lot more chaotic than previously thought.

[alexis]

The hot Jupiters are thought to be produced by planet migration due to planet-disk interaction, not planet-planet interaction. There is a group at our institution doing massive parallel simulations of this very problem (on twenty connected Athlon 1800+ CPUs!). For a readable recent review on planet formation (written by Pawel Artymowicz), please see this pdf (200 kB), soon to be published as proceedings from a conference I happened to attend.

/Alexis

[alexis]

PS Velikovski's ideas were much more crazy than this

[marc]

Since my program, StarGen, has been mentioned here a couple of times using different URL's, I thought I'd post the official one. (Sadly, due to the actions of my original ISP it has changed a couple of times in the past few months, but with a new ISP and an assist from ZoneEdit, it is back where it belongs and will hopefully stay stable. Sorry for the inconvenience.)

StarGen's web page can be found at http://www.eldacur.com/~brons/NerdCorner/StarGen/StarGen.html.

StarGen is a random solar system generator based on the accretion disk model work first done about 3 dozen years ago at Rand by Stephen Dole. As another poster has pointed out, the model is obsolete, but it does create plausible looking solar systems. Since becoming a fan of Celestia a few months back, I've been working on adding support for creating .ssc files using it. That work is incomplete, but progressing.

Comments on StarGen are always appreciated.

Thanks,
Brons

I modified stargen to create the ssc files for the systems in mostlyharmless a while back. I hacked it pretty good though and made quite a mess of the source, but it works. Ive set it up to make heaps of systems at once but with a few changes it should be able to make single systems again.

Here is the utility and source that i created from stargen.
http://sourceforge.net/project/showfile ... _id=112678

Im currently working on having stargen fill out a database and then modifying celestia to read from that database.

cheers

[billybob884]

as far as the actual building of planets is concerned, i think i may have found a program that will help you a lot...
http://www.lysator.liu.se/~johol/fwmg/fwmg.html