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I'm presently working on a setting that involves a planet orbiting a secondary star, a Red Dwarf, (let's call her Star B) which in turn orbits a G/K class star (Star A). I intend for this planet to be habitable by humans, as well as some indigenous aquatic lifeforms, so the purpose is to balance orbits so that the planet is able to be warmed by both Star A and B, but not fried by either. Star B will need an orbit greater than 1 AU, so that Star A will not completely fry our planet, but some of the heat our planet receives must be from Star A (since we're dealing with a Red Dwarf as the alternative), so it can't be too far.
Now I present the problem. Since our planet will be orbiting Star B, the distance between the planet and Star A will constantly be shifting. This website suggests that a planet orbiting a Red Dwarf should be anywhere from .28 to .03 AU away from the said star, which means that every planetary orbit will increase and decrease the distance between the planet and Star A by .56-.06 AU (doubled, as the orbital distance is the radius). If you are able, an answer considering both of the possible extremes would most likely be the most informative (so that the reader could then infer the range in between the extremes). What sort of problems would this orbital deficit present? Would a dense atmosphere aide in the reparations of these problems?
I am not necessarily concerned with the heat of Star B, but rather how these differences in distance between Star A and the planet will affect the planet's temperature, and general habitability. Would every orbit of the planet cause seasons of sorts, much like Fox-Chan suggested, or would it barely impact the temperature of the planet?
PS - I have already planned for this planet to have a dense atmosphere and robust magnetosphere, due to its proximity to Star B, but I don't know if this would affect the problem I have presented at all.