Super Earth @ Alpha Centauri

[RalofTyr]

If a world does orbit in the Alpha Centauri system, it will most likely be a super earth with gravity times our own. Here's my reasoning, the interstellar accretion disk that obited Alpha Centauri A was massive, so massive it produced two additional stars!!! So, the system was probably full of super Jupiters that have since been ejected. Any thing that survived, especially if one of those super Jupiters didn't spin inward, would be worlds with great metalicity and mass!!!

My guess that any earth-like world there will be massive and more Venus like than Earth like.

Alpha Centauri B, on the other hand, if it evolved like our jovian worlds, but was simply more massive, would have a stable planetary system with terrestrial worlds probably similar to our's.

Or, I'm totally wrong and Alpha Centuari B was captured and Promixa Centauri is just a coincidence that it appears to have proper motion of the Centauri system.

[Noclevername]

Or, I'm totally wrong and Alpha Centuari B was captured and Promixa Centauri is just a coincidence that it appears to have proper motion of the Centauri system.

You could still be wrong even if they all came from the same disk. The mass of the accretion disk has no bearing on the size of the planets formed, it could just as easily be a scattering of smaller planets. Given the gravitational churning of 3 (or two-and-a-half) stars, planetary formation was likely disrupted a great deal, so a large number of asteroids and dwarf planets might be the result.

[EndeavorRX7]

If there is an earth like planet in the Centauri system and it had intelligent life equal to or very similar to us (they have radio, televison, etc..) would we be able to detect them. I wondered about this because if we couldn't then how are we gonna find life anywhere else? This is relatively right next door.

[Noclevername]

If there is an earth like planet in the Centauri system and it had intelligent life equal to or very similar to us (they have radio, televison, etc..) would we be able to detect them. I wondered about this because if we couldn't then how are we gonna find life anywhere else? This is relatively right next door.

They could very easily be intelligent and even civilized without having radio. We were, for several thousand years. Plus we had a few hundred thousand before we invented civilization.

[EndeavorRX7]

They could very easily be intelligent and even civilized without having radio. We were, for several thousand years. Plus we had a few hundred thousand before we invented civilization.

That's true. So let me be more specific....let's say they have advanced to what we are today could we detect their presence? Lets say just for example it was an exact replica of earth today.

[Noclevername]

That's true. So let me be more specific....let's say they have advanced to what we are today could we detect their presence? Lets say just for example it was an exact replica of earth today.

Discussed here. I think the consensus was that we might detect something, but not clearly enough to know it was intelligent in origin.

[Kaptain K]

A plus for Alpha Centauri A and B is that they are older than the Sun (5-6 billion years old vs 4.6).
The bad news is that planetary orbits are stable only out to about 2 AU from each star, which severely limits the number of planets either can have.

[trinitree88]

If there is an earth like planet in the Centauri system and it had intelligent life equal to or very similar to us (they have radio, televison, etc..) would we be able to detect them. I wondered about this because if we couldn't then how are we gonna find life anywhere else? This is relatively right next door.

Endeavor...we might see uranium spectral lines from the initiator A-bomb in their first H-bomb.....that'd be a clear sign of an intelligent civilization.....wouldn't it? pete

[ASEI]

I thought the metallicity of the planets in a star system was a function of the composition of the gas cloud (and the distance from the star, as the star would burn off volatiles in anything less massive than a jupiter sized planet)? Why would the mass of the accretion disk matter?

[eburacum45]

You might be interested in this paper:
Formation of terrestrial planets in close binary systems: the case of Alpha Centauri A (PDF)
http://arxiv.org/abs/astro-ph/0209118