[Space] Climate & habitability of tide-locked planets

[Agemegos]

¹ Joshi, M. M., Haberle, R. M., and Reynolds, R. T., 1997 Simulations of the Atmospheres of Synchronously Rotating Terrestrial Planets Orbiting M Dwarfs: Conditions for Atmospheric Collapse and the Implications for Habitability.

² When the entire planet is colder than what Joshi et al considered, naturally the dark side is colder than they concluded. CO₂ does freeze out on ice moons.

³ The modern consensus seems to be that 10 mbar of CO₂ will not freeze out with Earth-like solar heating, but that 3 mbar is unstable, and may.

⁴ In any inertial frame of reference.

⁵ Humans do not form permanent settlements where the average temperature is above 30 C or below 0 C. The reasons are probably agricultural, and would also rule out habitation where the photosynthetic photon flux density was too low to support the growth of crops.

⁶ Zeigler, J.F. and Cambias, J.L., 2006 Space. Steve Jackson Games, Austin TX.

⁷ Merlis, T.M. and Schneider, T., 2010 Atmospheric dynamics of Earth-like tidally locked aquaplanets.

⁸ I consider it unfortunate that the cases they published involved (a) one rotation per 24 hours, which is a lot faster than we expect for any habitability candidate, and (b) one rotation per 8 640 hours, which is a good deal slower than we expect for any habitability candidate.

⁹ The reason seems to be that Antarctica is isolated from tropical air by the Ferrel cell and polar easterlies, features produced by Coriolis effects. Since the anti-subsolar point in the tidally-locked Earth is not a rotational pole is it not similarly isolated from the global circulation, and there is no pool of cold air trapped on the dark face.

¹⁰ Hu Y and Yang J, 2013 Role of ocean heat transport in climates of tidally locked exoplanets around M dwarf stars.