The influence of surface CO2 condensation on the evolution of warm and cold rocky planets orbiting Sun-like stars

Abstract

The habitable zone is the region around a star where standing bodies of liquid water can be stable on a planetary surface. Its width is often assumed to be dictated by the efficiency of the carbonate-silicate cycle, which has maintained habitable surface conditions on our planet for billions of years. This cycle may be inhibited by surface condensation of significant amounts of CO2 ice, which is likely to occur on distant planets containing high enough levels of atmospheric CO2. Such a process could permanently trap CO2 ice within the planet, threatening its long-term habitability. Recent work has modeled this scenario for initially cold and icy planetary bodies orbiting the Sun. Here, we use an advanced energy balance model to consider both initially warm and cold rapidly-rotating planets orbiting F - K stars. We show that the range of orbital distances where significant surface CO2 ice condensation occurs is significantly reduced for warm start planets. Star type does not affect this conclusion, although surface CO2 ice condenses over a larger fraction of the habitable zone around hotter stars. The warm start simulations are thus consistent with 1-D model predictions, suggesting that the classical habitable zone limits in those earlier models are still valid. We also find that the cold start simulations exhibit trends that are consistent with those of previous work for the Sun although we now extend the analysis to other star types.

A New 2D Energy Balance Model for Simulating the Climates of Rapidly and Slowly Rotating Terrestrial Planets

“…My new 2D advanced EBM (PlaHab) is itself derived from a family of similar 1D latitudinally dependent codes (e.g., North & Coakley 1979;North et al 1981;Williams & Kasting 1997;Ramirez & Levi 2018;Bonati & Ramirez 2021). As with these and other 1D EBMs, PlaHab follows the radiative energy balance principle that planets in thermal equilibrium radiate as much energy to space as they receive from their host stars.…”

“…In our solar system, EBMs have now studied the climates of both present and early Mars (e.g., Armstrong et al 2004;Savijarvi et al 2004;Batalha et al 2016;Hayworth et al 2020). Exoplanetary applications have been particularly numerous and include (but are not limited to) studies that have assessed the variation of planetary/ orbital parameters on planetary habitability (e.g., Spiegel et al 2008Spiegel et al , 2009Dressing et al 2010;Spiegel et al 2010;Armstrong et al 2014), evaluated the strength of the CO 2 ice-albedo feedback for both warm-and cold-start planets (e.g., Kadoya & Tajika 2014;Haqq-Misra et al 2016;Kadoya & Tajika 2016;Haqq-Misra et al 2019;Bonati & Ramirez 2021), investigated water-ice coverage in habitable zone planets (Wilhelm et al 2022), examined water worlds (Ramirez & Levi 2018), studied Milankovitch cycles in planets orbiting binary stellar systems (e.g., Forgan 2014; Quarles et al 2022), addressed exomoons (Williams & Kasting 1997;Forgan & Dobos 2016), developed the habitable zone for complex life (Ramirez 2020a), and determined the impact of atmospheric pressure on habitable zone boundaries (e.g., Vladilo et al 2013Vladilo et al , 2015Ramirez 2020b).…”

CO2 Ocean Bistability on Terrestrial Exoplanets

“…Further, even with rapid tectonic resurfacing, the particular climate and/or arrangement of land on a given planet may not allow for high enough weathering fluxes to match outgassing rates, as we will go on to demonstrate. For these cases, it is important to note that surface CO 2 condensation can act as another major sink of atmospheric CO 2 (Kasting, 1991;Wordsworth et al, 2010b;von Paris et al, 2013;Turbet et al, 2017;Kadoya & Tajika, 2019;Bonati & Ramirez, 2021). As a result, under CO 2 -condensing conditions, it is possible for the carbon cycle to reach equilibrium even when outgassing does not equal weathering, as condensation can make up the difference,…”

“…Planets of the latter variety might be difficult to remotely distinguish from more traditionally "Earth-like" planets lacking surface CO 2 condensation at equivalent orbits, but the geochemistry and potential habitability of these worlds would be radically different, even with a temperate surface climate. Most previous examinations of surface CO 2 condensation on terrestrial (exo)planets have focused on cold, glaciated climates where CO 2 would only condense as a solid (Turbet et al, 2017;Kadoya & Tajika, 2019;Bonati & Ramirez, 2021); waterworlds with high pressure ice mantles (Ramirez & Levi, 2018;Marounina & Rogers, 2020); or the potential for CO 2 condensation on Mars in the deep past (Kasting, 1991;Forget et al, 2013;Soto et al, 2015). In this study, we focus on surface CO 2 condensation on rocky exoplanets with temperate climates in different end-member weathering regimes that inform the anticipated diversity of potentially habitable planets (Kasting et al, 1993;Wordsworth et al, 2010b;von Paris et al, 2013).…”

Functionality of Ice Line Latitudinal EBM Tenacity (FILLET). Protocol Version 1.0. A CUISINES Intercomparison Project

“…A number of subsequent works have studied potentially habitable exoplanets with diverse orbits and rotational properties (Spiegel et al 2008(Spiegel et al , 2009(Spiegel et al , 2010Dressing et al 2010;Armstrong et al 2014;Forgan 2014Forgan , 2016May & Rauscher 2016;Checlair et al 2017;Rose et al 2017;Silva et al 2017;Deitrick et al 2018;Haqq-Misra et al 2019;Okuya et al 2019;Palubski et al 2020;Yadavalli et al 2020;Wilhelm et al 2022). Others have focused on atmospheric or surface properties (Shields et al 2013;Vladilo et al 2013;Haqq-Misra 2014;Kadoya & Tajika 2014, 2016Menou 2015;Haqq-Misra et al 2016;Ramirez & Levi 2018;Rushby et al 2019;Ramirez 2020a;Bonati & Ramirez 2021;Haqq-Misra & Hayworth 2022). Thus, a rich body of literature applying EBMs to exoplanets exists.…”