Tidal Lock

[Moontanman]

A new planet was discovered recently orbiting Proxima Centauri, Earth like in both size and habitable zone orbit it has of course fueled considerable speculation.

 

The planet is thought to be so close, orbital period or year is 11.5 Earth days, that it is tidally locked with it's star keeping one side facing the primary much like the moon does the earth.

 

In our own Planetary system The Planet Mercury was once thought to be tidally locked due to it's close proximity to the Sun but it is now known Mercury rotates on its axis exactly three times for every two revolutions it makes around the Sun.

 

Could this new planet also be orbiting in this manner due to the same or similar forces that cause Mercury to do so?

 

This would indicate a possible ecosystem that follows the terminator instead of one side bathed in light and the other forever dark.

 

Have any weather studies been done for this possibility? I have seen some weather studies for tidally locked planets but not for ones that rotate very slowly...

[Ophiolite]

Isn't Mercury's rotational period a consequence of gravitational interaction with the other planets, especially Venus? If this is the case then were it true for PCb we might expect to have seen evidence for these other planets, since we may presume they orbit in a similar plane and should therefore also produce a detectable dimming?

[Airbrush]

If the planet is in the habitable zone then anything is possible. Even if tidally locked, the twilight zone would be very interesting.

 

If we only recently discovered that Mercury is not really tidally locked, then an exoplanet could be also mischaracterized.

Edited September 9, 2016 by Airbrush

[Moontanman]

If the planet is in the habitable zone then anything is possible. Even if tidally locked, the twilight zone would be very interesting.

 

If we only recently discovered that Mercury is not really tidally locked, then an exoplanet could be also mischaracterized.

 

 

If the twilight zone was consistently moving then any culture might be nomadic, following the terminator. If the terminator moved along the lines of a few weeks or months with might be tolerated like winter is here on earth.

 

Lots of interesting strangeness! What a great time to be alive!

Isn't Mercury's rotational period a consequence of gravitational interaction with the other planets, especially Venus? If this is the case then were it true for PCb we might expect to have seen evidence for these other planets, since we may presume they orbit in a similar plane and should therefore also produce a detectable dimming?

 

 

Good point, not sure if the planet was found due to dimming or due to doppler effect...

[Janus]

A new planet was discovered recently orbiting Proxima Centauri, Earth like in both size and habitable zone orbit it has of course fueled considerable speculation.

 

The planet is thought to be so close, orbital period or year is 11.5 Earth days, that it is tidally locked with it's star keeping one side facing the primary much like the moon does the earth.

 

In our own Planetary system The Planet Mercury was once thought to be tidally locked due to it's close proximity to the Sun but it is now known Mercury rotates on its axis exactly three times for every two revolutions it makes around the Sun.

 

Could this new planet also be orbiting in this manner due to the same or similar forces that cause Mercury to do so?

 

This would indicate a possible ecosystem that follows the terminator instead of one side bathed in light and the other forever dark.

 

Have any weather studies been done for this possibility? I have seen some weather studies for tidally locked planets but not for ones that rotate very slowly...

I just did a quick "back of the Envelope" calculation comparing the tidal braking effect on Mercury to that of an Earth-sized planet orbiting Proxima, at the distance needed for the Given Orbital period. It works out to be several thousands of time greater for Proxima's planet than it is for Mercury. Tidal braking is heavily dependent on the distance between planet and star, much more so that it depends on the mass of the star. For the planet to orbit Proxima (a less massive star than the Sun) in 11.5 days, it is going to have to have a very small semi-major axis.

Given this, I doubt that even perturbing effects from other planets would not be enough to keep it from tidal locking in a very short time.