I'm attempting to figure out the orbital physics of a system that has a habitable body that has intense periods of waxing and waning sunlight. I've come to the assumption that the best body for this to happen on would be the moon of a gas giant as I can use the gas giant to periodically shield the planet from star.
This is not something I'm an expert in at all so hoping for help in figuring out what it would take for this scenario to be possible. If it's possible at all.
So here's a lot of information on what type of system I'm thinking about, more details will be added as they come up.

Goals for the moon :

• Hemisphere A is habitable all the time, even if the environment gets harsh at times, the colonists have means to deal with temperatures up to 60-70 degrees Celsius. Majority of the primary colony and outliers are within exposed cave systems.
• Atmosphere is breathable by humans
• Gravity within 10% of earths, size doesn't matter much to me but should support cave systems
• Developed basic life - mosses, fungus, primitive leafing things, insects, and amphibians. So the system in place has to have been stable enough to allow for life to develop.
• It's not the only moon around the planet, but only one that has developed life and can sustain humans without creating habitats.

Creating "Sunfall"

• The moon should go through periods of time say 100-200 years where humans and other life can spread to 60-100% of the moon. Temperatures should reach points where no type of environmental suits are required.
• The moon needs to go into Sunfall periods of 40-100 years where greater than 50% of the moon will be cooked. Sustained temperatures for long periods of time that will cause plant life to burn/die and would be lethal to humans exposed for more than 5-10min, either due to heat or radiation.
• Sunfall isn't required to be constant, but last long enough and happen enough that it's not feasible for life to come back until Sunfalls stop, or their frequency drops to a certain point.

Flexible with :

• It doesn't 100% have to be a moon, I'm just not sure how you'd do this with a planet...would be incredibly awkward combination of things.
• Environment can be extreme, but humans should be able to survive in the safe region without much in the way of equipment.
• Colonists are used to weird days and living in cavern systems, they have clocks based on far-flung home planet so rotational and orbital periods don't matter as long as they work.
• The type of star, or size and composition of the parent planet
• Cooler periods can be longer, but I'd like to not have Sunfall last more than 1-2 generations of humans.

What would a system look like to get phenomenon like "Sunfall" on a celestial body? If this doesn't seem possible that's also something I'm willing to accept and consider alternate possibilities giving similar impacts on the environment.

Thanks!

I'm attempting to figure out the orbital physics of a system that has a habitable body that has intense periods of waxing and waning sunlight. I've come to the assumption that the best body for this to happen on would be the moon of a gas giant as I can use the gas giant to periodically shield the planet from star.

This is not something I'm an expert in at all so hoping for help in figuring out what it would take for this scenario to be possible. If it's possible at all.

So here's a lot of information on what type of system I'm thinking about, more details will be added as they come up.

Goals for the moon :

• Hemisphere A is habitable all the time, even if the environment gets harsh at times, the colonists have means to deal with temperatures up to 60-70 degrees Celsius. Majority of the primary colony and outliers are within exposed cave systems.
• Atmosphere is breathable by humans
• Gravity within 10% of earths, size doesn't matter much to me but should support cave systems
• Developed basic life - mosses, fungus, primitive leafing things, insects, and amphibians. So the system in place has to have been stable enough to allow for life to develop.
• It's not the only moon around the planet, but only one that has developed life and can sustain humans without creating habitats.

Creating "Sunfall"

• The moon should go through periods of time say 100-200 years where humans and other life can spread to 60-100% of the moon. Temperatures should reach points where no type of environmental suits are required.
• The moon needs to go into Sunfall periods of 40-100 years where greater than 50% of the moon will be cooked. Sustained temperatures for long periods of time that will cause plant life to burn/die and would be lethal to humans exposed for more than 5-10min, either due to heat or radiation.
• Sunfall isn't required to be constant, but last long enough and happen enough that it's not feasible for life to come back until Sunfalls stop, or their frequency drops to a certain point.

Flexible with :

• It doesn't 100% have to be a moon, I'm just not sure how you'd do this with a planet...would be incredibly awkward combination of things.
• Environment can be extreme, but humans should be able to survive in the safe region without much in the way of equipment.
• Colonists are used to weird days and living in cavern systems, they have clocks based on far-flung home planet so rotational and orbital periods don't matter as long as they work.
• The type of star, or size and composition of the parent planet
• Cooler periods can be longer, but I'd like to not have Sunfall last more than 1-2 generations of humans.

What would a system look like to get phenomenon like "Sunfall" on a celestial body? If this doesn't seem possible that's also something I'm willing to accept and consider alternate possibilities giving similar impacts on the environment.