: : : : : : I'm a complete novice to astronomy but am interested in some "expert" opinions for some fiction I am considering writing. What I'd like to know is whether its possible that an inhabitable (by humans) planet might orbit Alpha Centauri 1 in such a way that it actually passes between Alpha Cent. 1 & Alpha Cent. 2, during its year. Is that possible and if it is, what might conditions be like on such a planet? I do not know how close together the stars of the Alpha Centauri system are to one another but I assume there is plenty of room for a planet to orbit one of them? I'm looking for feasible stuff for the imagination here. : : : : Thanks.

: : : No way can a planet survive in the Centauri system, : : : there are three stars about couple hundred AU's from : : : each other, their gravitational pulls would neither : : : make the planet collide with a star or gain speed : : : and escape into space. If there is a planet, it could : : : be a gas giant like Jupiter. I suggest you use stars : : : like 51 Pegasi or 47 Ursae Majoris, they are stars that : : : have been proven to have planets.

: : Thanks. I'll do some more research. : ************************************* : ************************************* : Although there has been no discovery of a planet, : recent research projects have shown that planets could : indeed be orbiting either Alpha Centauri A or B. A standard rule of thumb is that stable planetary orbits can be found in multiple systems if those orbits are no more than 1/5 the distance to the nearest neighbor. In the case of Alpha Centauri, this works out to about 5 AU for both stars. There are other matters to take into account, but in general, this works quite well for this system. Proxima Centauri, liekly to not even be physically associated with this system, is so far away from the primary members that it could have a large system of planets indeed. Of course, it is too dim to allow for life, as far as we know....