Heating a gas giant's moons in a red dwarf system

Being new, this is my first question. I've read some other posts that gave me valuable insight, but I still have some questions.

First, some specifics:

• Star: red dwarf. 80 x jupiter mass. 3 billion years old, after the violent flare phase.

• Gas giant: 7 x jupiter mass (edited from 12, so its not a brown dwarf). Almost white, 0.75 - 0.85 albedo, the more the better. Let me know if this is not possible.

• They orbit around each other. I want an orbital period of 1 year for the planet. That would need a distance between them of around 0.45 AU (according to US2).

• 2 earth-sized moons tidally locked to the gas giant with orbital resonance of 2:1. They have water and earth-like atmospheres (maybe a bit more CO2 for greenhouse effect). However, they will probably be frozen.

So... does the gas giant have a good way to heat up its moons' surfaces to human-friendly temperatures (0 - 30 celsius average)? Like... how close the moons have to be for tidal heating to be a factor without destroying them? Also, the gas giant has high albedo, can it heat up its moons by redirecting star light (planet so big and white that creates a secondary day in the parts of the moons facing it...)? Are there other ways for the gas giant to heat up its moons?

Extra: if all the ways the gas giant have to heat up its moons combined are not enough and the moons just stay frozen... How much more massive does the red-dwarf have to be for the moons to achieve the desired temps? (mantaining all the rest the same, specially the 1-year orbital period)

If relevant: I want a system that can harbor human life for a much longer time than our system can. That's why I chose a red dwarf after its flare phase and earth-sized moons (to avoid tidal locking to the star), but I want the orbital period to be 1-year... and with a red dwarf that means really cold moons, so the gas giant providing heat is a solution I thought could work. However, I have no idea what the numbers are or if the gas giant actually has a way to heat up its moons. Maybe I need a heavier star, but if it's not as massive as the sun that's still a win for me.

posted almost 5 years ago

Diego Cruz Barreto‭

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