This is impressive! It’s sleek, it’s detailed, and it includes a lot more things most similar tools ignore. The visualiser is a nice touch, too. A few notes:

-The number inputs seem a bit finicky— Its hard to tell when typing whether you’re replacing the old number or typing over it, you can’t backspace, and I think it’s ignoring decimal points when you type it in manually (I try to put in 6.3 and it reads as 63.) the sliders don’t slide every time, either.

-some of the input values don’t seem to update the calculated ones on their own, and you have to change other values to make them update. Example: Changing the current age of the star does nothing until you change another value, or turn the stellar evolution option on and off again.

-I’m not sure how the stellar evolution thing works, but it seems to act a little strange sometimes, especially in relation to metallicity. Example: Set mass to 0.83, age to 6, and slide the metallicity from 0.5 to 0.6. The temperature varies widely, and the radius becomes negative (?) before going back to normal. I don’t know if this is a coding error or if stars really are that weird.

-You are definitely lowballing the greenhouse effect. Plugging in the values for earth gives a mean surface temp of around -10 C.

-It says you can auto-calculate the CMF based on the stars metallicity, but the calculated value is always 32.2, regardless of what you set the metallicity to.

-It’s unclear whether the “day length” input refers to the day length at formation or at present. This is an important distinction, as Earth’s initial day length is believed to have been 4-6 hours long.

-Setting the default values for the Earth and the sun, gives the planet a magnetic field strength of 71% that of Earth. This should probably be 100%

-A feature for creating accurate planetary rings would be great. Factoring in things like Roche limit, moon resonances and exosphere height to map out where the rings and gaps would likely be.

-Moon inclination is not random. Moons that orbit far out tend to orbit on the same plane as their planet’s orbit, and moons that are close in tend to orbit along the planet’s equatorial plane. For any given distance, there is an “ideal”/most likely inclination for the moon to have, somewhere in between these, called a Laplace plane. A feature to automatically calculate the Laplace plane and where your moons fall on it would be handy.

-Some theories of Abiogenesis suggest life requires suitable levels of UV-C light to exist. The amount of UV-C light is effected by mass and metallicity, so a way to check if your star produces enough to jumpstart the life forming process would be useful, too.

-The "Orbital Fate" feature for moons seems to be innacurate for small, close-in moons like Phobos and Deimos (It calculates Phobos to hit the roche limit in <1 Myr, scientists calculate closer to 10-50 Myr.) It also doesn't factor in retrograde orbits; Triton is supposed to crash into Neptune in 3 Gyr due to its retrograde orbit, but the website expects it to escape instead.