1) What do you think the odds now are of there being a planet somewhere in the Alpha Centauri system?

Hazarding a guess, I’d say 60%. A better answer might be, “High enough to warrant mounting an inexpensive (in comparison to most other planet-search efforts in operation or contemplation) ground-based search.”

2) How long will it be before we can confirm that there are no such planets through direct observation, if they don’t exist?

Assuming that the Alpha Cen B continues to cooperate with the radial velocity observers, we’ll know in five years whether there are any planets in the system that are Earth-mass or above. In three years, we’ll have an very good indication of what’s going on.

3) With the recent direct imaging successes with Hubble, what are the chances of catching planets around the nearest star.

We know that there aren’t any circumprimary Jovian-mass planets in the Alpha Cen system, and the system is ~7 billion years old, so direct imaging with Hubble isn’t an option. RV is the only near-term option.

Fom b is a very young planet, probably surrounded by a moon-forming circumplanetary disk, making it much easier to detected if it were otherwise. Also, Fom b has a semi-major axis of 119 AU — pretty far from Fomalhaut itself.

HR 8799 and company were detected in infrared. This is feasible as they are very young and still glow with the heat of their formation.

Alf Cen, on the other hand, is a mature, binary system. The semi-major axes of the Alf Cen stars is ~30 AU if I recall correctly, so any planets should be significantly closer to either star than Fom b is to Fomalhaut, or HR 8799 b, c, or d, are to their host.

Admittedly this is not a young system putting out Infrared radiation but the proximity calls out for an attempt.

Is this at all worth while?

1) What do you think the odds now are of there being a planet somewhere in the Alpha Centauri system?

2) How long will it be before we can confirm that there are no such planets through direct observation, if they don’t exist?

I understand it’s all speculation, but I am curious what the experts think as the evidence (one way or the other) accumulates.