This is because enhanced dayside convection produces thick and reflective water

This is because enhanced dayside convection produces

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rotating. This is because enhanced dayside convection produces thick and reflective water clouds near the substellar point, reducing the net absorbed stellar flux and cooling the climate, which permits clement mean surface temperatures closer to the star [ 237 ]. Yang et al. [ 238 ] had originally found that HZ planets orbiting F–M stars can remain habitable at distances corresponding to stellar fluxes that could be more than twice (>200%) those predicted for the classical 1D HZ (e.g., [ 1 , 26 ]). However, synchronously-rotating HZ planets may only be common around late K- and M-stars [ 177 ], because HZ planets orbiting hotter stars are well outside the tidal-locking radius (e.g., [ 1 , 177 ]). Subsequent GCM studies, focusing on K- and M-stars, then found that the rotational and cloud effects in Yang et al. [ 238 ] had been overestimated because of orbital period scaling issues [ 239 ]. Later works with improved radiative transfer [ 27 ] and convection schemes [ 240 ] determined that rotation rates and clouds have a much smaller effect on the classical inner edge than had been previously thought. The Bin et al. [ 240 ] CAM5 simulations found that S EFF was only 0–50% larger for slow rotators, which translates to a modest ~0–19% decrease in inner edge distance (assuming a stellar luminosity of 0.7 L /L sun for the T EFF = 4400 K K-star) (Figure 14 ). However, there is reason to believe that the inner edge contrast between slowly- and rapidly-rotating planets in these simulations is still being overestimated. Previous calculations had been performed using idealized slab ocean GCMs that lack proper equator-pole ocean heat transport. In reality, ocean dynamics should reduce the day- to night-side temperature contrast (e.g., [ 241 ]), as may also be expected from the Second Law of Thermodynamics. Thus, the calculation for K–M-stars should be repeated with models that dynamically couple the atmosphere and ocean. In any case, if 1D and 3D inner edge estimates are similar to one another for hotter stars, as recent studies suggest (e.g., [ 1 , 25 , 242 , 243 ]), it is probably more likely that Venus lost its water early in its history (e.g., [ 50 ]) rather than later (e.g., [ 238 , 244 ]).
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Geosciences 2018 , 8 , 280 28 of 48 slab ocean GCMs that lack proper equator-pole ocean heat transport. In reality, ocean dynamics should reduce the day- to night-side temperature contrast (e.g., [241]), as may also be expected from the Second Law of Thermodynamics. Thus, the calculation for K–M-stars should be repeated with models that dynamically couple the atmosphere and ocean. In any case, if 1D and 3D inner edge estimates are similar to one another for hotter stars, as recent studies suggest (e.g., [1,25,242,243]), it is probably more likely that Venus lost its water early in its history (e.g., [50]) rather than later (e.g., [238,244]). Figure 14. Summary of recent 1D and 3D model estimates of the location of the inner edge for mid- K- to M-stars. The Leconte et al. [25] curve is the nominal inner edge estimate for rapidly-rotating planets, superseding the previous estimate [26]. The remaining limits are various 3D estimates for synchronously-rotating worlds.
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