I'd like to suggest using a program/game called Universe Sandbox (I bought it on Steam for $9.99). they are coming out with a new one soon, but i have the original (not sure if you guys/gals have been using this, i only read the first few posts and skimmed them at that). I bought it to run simulations for the world i am creating. Similar to what i have read here, i wanted my planet to orbit a White Dwarf star, so i wanted to get the yearly orbit and temperature of the planet the way i wanted. the following is the information i used when creating my system.

Star:

Mass: 4.29 Suns
Diameter: 465188 km (bigger than i originally wanted, but seems to work in the model i made)
Density: 162 grams per cubic centimeter (g/cm^3)

Temperature: 12050 Kelvin (Our sun is 5000ish Kelvin)
Luminosity: 2.12 L (earth's sun = 1 L, this brightness can be dimmed by atmospheric conditions)

it is blueish white

Planet:

Mass: 1 earth
Diam: 23853 km (Almost twice the size of Earth, but that's because my world lacks sufficient metals and it has to be bigger to equal the mass needed to have Earth like weight)
Density: .84 g/cm^3

Average Temp: 17.6 C or about 63 F. (close to Earth)
Orbital period 300 days (the gravity of the sun causes the years to be shorter, since the planet is orbiting it faster, at 365 days the temp would be too cold)

Moon:

Mass: 1 Lunar mass
Diam: 4586 km
Density: 1.46 g/cm^3
Avg Temp: 17.4 C or About 63 F (my moon has an atmosphere and would be able to support life if the inhabitants of the planet had the technology and means to reach it)
Orbital period: 30 days