Is it time to rule out planets at Alpha Centauri?

[PlutonianEmpire]

I recall reading on an astronomy magazine a few years ago, that the movie Avatar (the James Cameron one) was "ten years behind the times", because radial velocity measurements ruled out the possibility of giant planets in the system.

However, as I said, that was a few years ago. Since then, I still have not heard anything about Alf Cen planets, except that component B "should have planets", based on metallicity measurements.

Considering the system is so close to Sol, we should have discovered at least a super-earth by now. Still, zip.

It is mentioned that the HZ's of both components are right on the border of orbital stability for hypothetical planets.

Considering the system has been studied for so long, might the presence of planets around either component need to be ruled out? Or is there still a ways to go on this subject?

[ajtribick]

Last I heard, there's still some way to go... the upper limits on the mass of any planets there are coming down (I heard reports that it was down to 4 Earth masses for objects with orbital periods less than 300 days around Alpha Centauri B), but I don't think we can rule out Earth-mass objects yet.

And of course there's always the possibility that the planetary system there only contains Mars-mass objects and smaller (for example), it is going to be a long time before we can rule that kind of thing out.

[aurora]

There can also reasonably be a largish circumbinary gas/ice giant in an outer orbit.