Alpha Centauri / Proxima Centauri

[T.Neo]

The habitable zone of a dwarf star is virtually not existent because of tidal locking, but the radiation is identical by the definition of habitable zone.

If the planet had a thick enough atmosphere, tidal locking would not be a hurdle to habitability.

It would, however, cause the nightside of the planet to be permanently covered in
ice and cause large portions of the dayside to be undesirably warm and turbulent.

 

[Urwumpe]

If the planet had a thick enough atmosphere, tidal locking would not be a hurdle to habitability.

Venus is de-facto tidal locked, the very dense atmosphere does not prevent thermal stress inside it.

 

[T.Neo]

Venus is de-facto tidal locked, the very dense atmosphere does not prevent thermal stress inside it.

I never said it did not.

The Venusian surface temperature does not change much from the dayside to the nightside.

The atmosphere should carry sufficient heat to the night side at only 10% Earth's atmospheric pressure. See abstract here and wiki page to M dwarf habitability here.

 

[donatelo200]

T.neo is right. A flare isn't strong enuph to ionize a planets atmosphere or boil water away. But over a long period of time, the flares and the solar wind can strip a planet of most (if not all) of a planets atmosphere and liquids.(mars for example) But, this will only occur if the planet has either a weak or no magnetic field.

 

[Deltafang]

Intelligent debate is always fun.

So we're in agreement that there could be a life bearing planet in Alpha Centuari? Anyone know what the goldilocks zone is for Alpha Centuari?

I also hear that there's a rough chance of there being any gas giants within the system, I'll supply the link when I find it again.

 

[T.Neo]

Alpha Centauri is a system that consists of Alpha Centauri A and Alpha Centauri B, which are G and K class stars. Proxima Centauri is an M class star that is somewhat more distant and may or may not be a stellar companion to the other stars.

The chance of a jovian planet orbiting either ACA or ACB is rather slim as I understand, due to the fact that we would already have found a planet that massive.

As for habitable planets orbiting either star, the only hurdle would be disturbance from the other star. I've heard figures of stable orbits of only 250 million years for a planet in the habitable zone.

However if the orbits are stable enough, there is a high chance that there could be a habitable planet there that we simply haven't detected yet.

The notion of a "Goldilocks" zone or habitable zone is a fuzzy one, and highly dependant on the planet. The habitable zone for ACA would be slightly larger then that of the sun and the habitable zone for ACB slightly smaller, I'd imagine. But not by considerable amounts.