Is it possible for a planet to be ejected from one star system and end up in the habitable zone of another? Or do captured planets always end up in wide, eccentric orbits? I guess in the vast expanse of the Universe, it seems like this should be possible but maybe very unlikely?
For reference, there is an hypothesis according to which Venus is a captured planet. Evidence for this is her weird angular momentum (spins so that the Sun rises on the west, one sol lasts 224 Earth days). Do notice that current scientif consensus is that Venus was not captured, but rather spins retrograde due to her strong winds acting on her surface over geological eras. Her orbit is less eccentric than Earth's and she's almost in the habitable zone.
It may have been just luck of the draw that put Earth and Mars in the goldilock zone around the Sun but not venus. There is even another idea that every planet in our solar system formed in a different orbit and got moved to some other orbit, so...