Astronomers discover 7 Moon-sized planets orbiting nearby Gas Giant
Posted: Mon Feb 27, 2017 4:18 pm
Correcting the scaling error, you find the Trappist-1 "planets" have nearly identical orbital characteristics with: Miranda (b), Ariel (c), Umbriel (d), Titania (f) and Oberon (g), the periods being off by about 5% for b, c, d and f, and 9% for g.
All of these 7 moons are approximately 75% the size of our own moon.
moon: period(d) / Diameter(km) / Semi-major Axis(km)
b: 1.51/1384/166203 → Miranda: 1.41/471.6/129390
c: 2.42/1346/227688 → Ariel: 2.52/1353/191020
d: 4.05/984/314156 → Umbriel: 4.14/1169/266300
e: 6.1/1170/418874
f: 9.2/1332/553512 → Titania: 8.7/1577/435910
g: 12.35/1436/673190 → Oberon: 13.46/1523/583520
h: 20/962/942467
Since Trappist-1 is smaller than Uranus, the semi-major axis measurements are off by almost exactly 20% (0.78, 0.84, 0.85, 0.79, 0.87) for all the comparisons. That would make the "star," itself, have a diameter of 20447 km, or about 3.2x the size of the Earth.