Time for a quick taste of how the new Architect of Worlds version is turning out.

Long-time followers of this project will remember the two running examples in the draft: planetary systems named Arcadia and Beta Nine that are intended to demonstrate how the system works in practice. I’m in the process of re-working all of the examples, which should be the last step before I share the current draft with my patrons and my readers here.

Here are a couple of tables to suggest some of the results of the revised system.

Arcadia Planetary System
Orbital Radius	Planet Type	Planet Mass	Density	Radius	Surface Gravity
0.254 AU	Terrestrial Planet	0.26	0.75	4470 km	0.53 g
0.380 AU	Terrestrial Planet	1.75	1.09	7460 km	1.28 g
0.580 AU	Terrestrial Planet	1.34	1.10	6800 km	1.17 g
1.00 AU	Terrestrial Planet	0.22	0.74	4250 km	0.49 g
2.12 AU	Planetoid Belt	N/A	N/A	N/A	N/A
4.08 AU	Large Gas Giant	460	0.20	84100 km	2.64 g
8.12 AU	Medium Gas Giant	180	0.075	85300 km	1.00 g
12.0 AU	Small Gas Giant	52.0	0.14	45800 km	1.00 g
17.6 AU	Failed Core	2.80	1.13	8620 km	1.53 g

Not too many surprises here – this resembles the previous version’s Arcadia system fairly strongly. For some context, the primary star here is a singleton K2V, with about four-fifths the mass and one-third the luminosity of Sol. The third planet (at 0.58 AU) is the Earthlike candidate that I intend to use as an example for the last portion of the design sequence.

Beta Nine Planetary System
Orbital Radius	Planet Type	Planet Mass	Density	Radius	Surface Gravity
0.027 AU	Terrestrial Planet	1.22	1.09	6610 km	1.13 g
0.038 AU	Terrestrial Planet	0.94	1.01	6220 km	0.99 g
0.062 AU	Planetoid Belt	N/A	N/A	N/A	N/A
0.135 AU	Small Gas Giant	12.0	0.29	22000 km	1.00 g
0.390 AU	Failed Core	2.80	1.16	8540 km	1.56 g

The Beta Nine primary is an M4V red dwarf, with about 0.18 solar masses and less than 1% of Sol’s luminosity. It also has a brown-dwarf companion that cuts off planetary formation too far away from the primary. This planetary system is actually quite a bit different from the previous draft’s Beta Nine. The new model I’m using provides enough planetesimal mass for at least a small gas giant world, and it also allows for the possibility that some of that planetesimal mass “migrates” into the inner system to help form rocky worlds. So we end up with more planets this time, and the terrestrial worlds are considerably bigger.

One inspiration here is the TRAPPIST-1 planetary system. My old model didn’t have much trouble generating a planetary system like that for a small red dwarf, but it needed a pretty massive protoplanetary disk to do it. Under the new model, a red dwarf star doesn’t need an improbably big disk mass to have a chance at Earth-sized worlds. Given how many red dwarfs we’ve found with planets of significant size, I suspect the new model fits the facts better.

I’m hoping to have the new draft out as a free update for my patrons, and as an update to the version posted on this site, within a few days.