Hello, I am a new member. I came here via a search trying to research for a piece of fiction I am attempting to write. However, now I just wish to pose this as a hypothetical problem. I have no idea if this is the right section of the forum for this, but I am guessing extra-solar planet research is as close a fit to the idea as anything else.
The idea was, with all variables open to adjustment, could there be a planet with noticeable seasons yet no axial tilt? For the fictional planet, I wanted a world with no separate seasonal patterns such as we have in the northern vs southern hemispheres. I also wanted there to be no times, in arctic/antarctic regions, where there are periods where the sun doesn't set or doesn't rise, hence the lack of a tilted axis for the hypothetical planet.
I imagine a planet with an orbit more eccentric than Earth's that allows it to span from one side of it's star's habitable zone to the other. There would also be one moon about the same relative size and distance from the planet as our own. I assume this would work so long as the eccentricity of the orbit does not lead to excessive temperature extremes that would incinerate or freeze life on the planet. While it might not have as well defined seasons as we have, would this still create a cycle of cooler - temperate - hotter - temperate - repeat? Could this even be imagined in such a way to mimic the seasons of one hemisphere of our planet?
Also, with these parameters, what would the effects be that would be different from our own world? I would imagine that with such an eccentric orbit there might be more volcanic activity from the tidal forces of the sun on the planet, such as can be seen on some of Jupiter's moons. But what other differences could be expected?
Any thoughts or impressions would be greatly appreciated. My knowledge of astronomy and geology consists of a single introductory college course each.
Thank you in advance to anyone who offers any ideas or commentary.