Conditions on Red Dwarf World: "Planet Cid"

[AceSuperVillain]

Hi, I'm Ace the Super Villain. Like many of you, I was overwhelmed with excitement over the discovery Gliese 581c. Sadly, there is next to nothing that is actually observable about the planet, so to satisfy my curiosity, I began researching other exoplanets and eventually came across the debates about what conditions would be like on a planet orbiting a Red Dwarf star. This is still of course, completely hypothetical, and I thought I'd like to add my own two-cents to the party.

Introducing the hypothetical, Planet Cid:
http://www.bluecloak.net/ace/Planet_Cid.PNG
(Sorry for the low-tech approach, but I didn't think Blender would really add anything to the science behind this.)

Planet Cid is a generic planet without any specific properties that could be found around any Red Dwarf star. There are however, a few assumptions made to move the hypothesis along:

1) Planet Cid is tidally locked to its star as all RD planets are expected to be and has a short orbital period
2) Planet Cid's orbital period is swift enough to facilitate a planetary magnetic field and prevent its atmosphere from blowing away
3) Planet Cid is in the "habitable zone", wherever that happens to be for Red Dwarfs
4) Planet Cid is roughly the same composition to Earth. (there is almost no chance of this being true, there aren't even any objects in our solar system that mimic Earth's composition, not even Luna, but I, as an Earthling, am ill equipped to deal with any other models)
The current model for Planet Cid does not explore natural satellites or native life forms.

Anyways, there are a few things that I would like to explore in the midst of a scientific community which are included in the illustration. The six poles are provided to aid discussion, North and South poles are in the usual place, Noon and Night poles are at the extreme sunward and anti-sunward points and the Fore and Aft poles are the front and back of the planet as it moves through space along its orbit.

1) Lagging Hydrosphere: It seems to me that if a planet were traveling quickly through space with all its sides always facing more or less the same direction, any "loose bits" would begin to collect towards the Aft Pole. Note that water also sloshes around on Earth in the form of the tides when Luna's gravity offsets Earth's position. There are however a myriad of different dynamics on Planet Cid than in our system, so I'm not sure about this.

2) Temperature Circulation: This is already a fairly prominent theory, the idea is that as the Noon-pole heats up, the air rises and colder air from the Night-pole swoops in to take its place, only to be replaced by the hot Noon air as it circles the planet. This wouldn't create a completely uniform global temperature, but it would make the moderate zone around the Terminator much larger and would prevent the Noon- and Night-poles from completely boiling off or freezing over.

3) Flatter Landscape: Theoretically, if Cid is a Super-Earth like Gliese 581c and d, the gravity would pull mountains down and flatten the planet, resulting in larger, shallower oceans and less geographical features such as mountain ranges. I'm not 100% sure about this, though I know Mars has less gravity and taller mountains and deeper canyons. This would however, further stabilize the planet's weather patterns since water has a more constant temperature than land and wind and rain would not be blocked by mountains (which is what creates deserts).

-=-

As you have probably guessed by my name, I am not a real scientist, so I would very much like to know what real scientists or at least people pretending to be them have to say about all this. I have plenty more theories about conditions on Planet Cid, such as tectonic conditions at the Noon-pole due to tidal heating, but this is long enough for now.

 

[neilsox]

~Most of that seems correct or likely~

Hi, Planet Cid is a generic planet without any specific properties that could be found around any Red Dwarf star.~According to another post, most red dwarfs are orange or yellow, but my guess is most of the light can be red and infrared if the photosphere is cool enough~ There are however, a few assumptions made to move the hypothesis along:

1) Planet Cid is tidally locked to its star as all RD planets are expected to be and has a short orbital period
2) Planet Cid's orbital period is swift enough to facilitate a planetary magnetic field and prevent its atmosphere from blowing away ~I don't think fast orbital speed makes magnetic field more likely~
3) Planet Cid is in the "habitable zone", wherever that happens to be for Red Dwarfs ~Typically only a few million kilometers above the photosphere~
4) Planet Cid is roughly the same composition to Earth. (there is almost no chance of this being true, there aren't even any objects in our solar system that mimic Earth's composition, not even Luna, but I, as an Earthling, am ill equipped to deal with any other models)
The six poles are provided to aid discussion, North and South poles are in the usual place, Noon and Night poles are at the extreme sunward and anti-sunward points and the Fore and Aft poles are the front and back of the planet as it moves through space along its orbit. ~fore and aft shift around the planets equator as Cid rotates around the Star

1) Lagging Hydrosphere: It seems to me that if a planet were traveling quickly through space with all its sides always facing more or less the same direction, any "loose bits" would begin to collect towards the Aft Pole. ~Assuming Cid travels in a high vacuum, very little collecting aft occurs~ Note that water also sloshes around on Earth in the form of the tides when Luna's gravity offsets Earth's position. There are however a myriad of different dynamics on Planet Cid than in our system, so I'm not sure about this. ~Cid would likely have a strong Sun tide, but only one rise and fall per Cid year = perhaps an Earth week/ Cid would loose it's moon in a few centuries if Cid ever had a moon~

2) Temperature Circulation: This is already a fairly prominent theory, the idea is that as the Noon-pole heats up, the air rises and colder air from the Night-pole swoops in to take its place, only to be replaced by the hot Noon air as it circles the planet. This wouldn't create a completely uniform global temperature, but it would make the moderate zone around the Terminator much larger and would prevent the Noon- and Night-poles from completely boiling off or freezing over. ~A thick atmosphere would help equalize the temperature planet wide/ Venus has only small temperature variations in spite of very slow rotation and revolving and no moon~

3) Flatter Landscape: Theoretically, if Cid is a Super-Earth like Gliese 581c and d, the gravity would pull mountains down and flatten the planet, resulting in larger, shallower oceans and less geographical features such as mountain ranges. I'm not 100% sure about this, though I know Mars has less gravity and taller mountains and deeper canyons. ~perhaps not/It is over 12 miles from the bottom of the Mariana Trench to the top of Mount Everest~ This would however, further stabilize the planet's weather patterns since water has a more constant temperature than land and wind and rain would not be blocked by mountains (which is what creates deserts).

tectonic conditions at the Noon-pole due to tidal heating, but this is long enough for now. Maybe. tectonic (or equivalent) is important to bring up fresh material from below the surface. Neil~

 

[AceSuperVillain]

Thanks for the reply, I'm relieved that it mostly seems to be on target. I think I should mention that I'm working with the information on http://en.wikipedia.org/wiki/Habitability_of_red_dwarf_systems as a starting point.

I guess now that you mention it, it does seem like the hydrosphere probably wouldn't lag as long as there's nothing to pass through causing drag. It also occurs to me that just because G581c has a 13 day year doesn't mean it's actually orbiting faster, just that the distance is less.

I'm still not convinced that Fore and Aft-poles would shift along the equator (assuming that the equator is parallel to the orbital plane like Earth's and not like Uranus') because the planet is not rotating due to tidal lock. If the planet was "rolling" then sure, each point along the equator would face the planet's direction of movement at some point in time. But as long as one point on the equator is always facing the parent star, then shouldn't one point always be facing in the orbital direction? I know they'd shift a little due to libration and eccentricity, but I don't think it would be much.