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Hayworth, B.; Kopparapu, R.; Haqq-Misra, Jacob; Batalha, Natasha E.; Payne, Rebecca; Foley, Bradford J.; Ikwut-Ukwa, Mma; Kasting, James F.

doi:10.1016/j.icarus.2020.113770

Cited by 27 publications

(24 citation statements)

References 58 publications

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“…The fact that factors like hydrology and soil age and lithology impact the effective outer edge of the HZ so strongly (see the top row in Figure 4) implies that a planet's susceptibility to limit cycling (and therefore its habitability) is determined by a complex interplay of factors that are not easily constrained a priori. Arguing that a given planet (e.g., Mars; Batalha et al 2016) experienced limit cycling thus requires making many implicit and potentially unfounded assumptions about the properties that controlled its weathering (see Ramirez 2017 andHayworth et al 2020) for further discussion of the early Martian limit cycling hypothesis). Kite et al (2011) use WHAK formulation of weathering to argue that there may be conditions where silicate weathering acts as a destabilizing feedback on the climates of rocky tidally locked planets.…”

Section: Relation To Previous Rocky Exoplanet Weathering Resultsmentioning

confidence: 99%

Thermodynamic and Energetic Limits on Continental Silicate Weathering Strongly Impact the Climate and Habitability of Wet, Rocky Worlds

Graham

Pierrehumbert²

2020

ApJ

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The "liquid water habitable zone" (HZ) concept is predicated on the ability of the silicate weathering feedback to stabilize climate across a wide range of instellations. However, representations of silicate weathering used in current estimates of the effective outer edge of the HZ accounts for neither the thermodynamic limit on the concentration of weathering products in runoff set by clay precipitation nor the energetic limit on precipitation set by planetary instellation. We find that when the thermodynamic limit is included in an idealized coupled climate/ weathering model, the steady-state planetary climate loses sensitivity to silicate dissolution kinetics, becoming sensitive to temperature primarily through the effect of temperature on runoff and to pCO 2 through an effect on solute concentration mediated by pH. This increases sensitivity to land fraction, CO 2 outgassing, and geological factors such as soil age and lithology, all of which are found to have a profound effect on the position of the effective outer edge of the HZ. The interplay between runoff sensitivity and the energetic limit on precipitation leads to novel warm states in the outer reaches of the HZ, owing to the decoupling of temperature and precipitation. We discuss strategies for detecting the signature of the silicate weathering feedback through exoplanet observations in light of insights derived from the revised picture of weathering.Unified Astronomy Thesaurus concepts: Habitable planets (695); Habitable zone (696); Exoplanet atmospheres (487); Exoplanet evolution (491)

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Section: Relation To Previous Rocky Exoplanet Weathering Resultsmentioning

confidence: 99%

Thermodynamic and Energetic Limits on Continental Silicate Weathering Strongly Impact the Climate and Habitability of Wet, Rocky Worlds

Graham

Pierrehumbert²

2020

ApJ

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“…Williams & Kasting (1997) used the one-dimensional radiative-convective climate model of Kasting (1991) and Kasting et al (1993) to calculate ∼300 values of F IR over a broad parameter space of T and pCO 2 , which was implemented as a best-fit fourth-order polynomial function. The planetary habitability model developed by Kasting et al (1993) has since been updated, and other studies (Batalha et al 2016;Haqq-Misra et al 2016;Hayworth et al 2020) likewise developed fourthorder two-piece polynomial functions for F IR based on hundreds or thousands of calculations with the improved radiative-convective model of Kopparapu et al (2013), which included additional representation of collision-induced absorption in dense CO 2 atmospheres. Polynomial representations like these are computationally efficient and allow for more realistic exploration of changes in climate to different forcing scenarios.…”

Section: Parameterizing Radiative Transfermentioning

confidence: 99%

“…This paper describes the habitable EBM for exoplanet observations (HEXTOR), which was originally developed by Williams & Kasting (1997) and has subsequently been updated for use in a range of studies for Earth (Haqq-Misra 2014), Mars (Fairén et al 2012;Batalha et al 2016;Hayworth et al 2020), and exoplanets (Haqq-Misra et al 2016. HEXTOR includes a newly improved lookup table method for calculating the outgoing infrared radiative flux and planetary albedo, which provides improvements over linear and polynomial representations that have been used in previous versions of the model.…”

Section: Introductionmentioning

confidence: 99%

An Energy Balance Model for Rapidly and Synchronously Rotating Terrestrial Planets

Haqq-Misra¹,

Hayworth²

2022

Planet. Sci. J.

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This paper describes the habitable energy balance model for exoplanet observations (HEXTOR), which is a model for calculating latitudinal temperature profiles on Earth and other rapidly rotating planets. HEXTOR includes a lookup table method for calculating the outgoing infrared radiative flux and the planetary albedo, which provides improvements over other approaches to parameterizing radiative transfer in an energy balance model (EBM). Validation cases are presented for present-day Earth and other Earth-sized planets with aquaplanet and land planet conditions from 0° to 45° obliquity. A tidally locked coordinate system is also implemented in the EBM, which enables calculation of the horizontal temperature profile for planets in synchronous rotation around low-mass stars. This coordinate-transformed model is applied to cases for TRAPPIST-1e as defined by the TRAPPIST Habitable Atmosphere Intercomparison protocol, which demonstrates better agreement with general circulation models than with the latitudinal EBM. Advances in applying EBMs to exoplanets can be made by using general circulation models as a benchmark for tuning as well as by conducting intercomparisons between EBMs with different physical parameterizations.

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“…A serious issue for global warming in this scenario is the anthropogenic emission of CO 2 into the atmosphere. 1 Tackling CO 2 emission in a large scale is possible by using the carbon capture and storage (CCS) technique, and this is considered to be a promising technology. The dual challenge for CCS is to minimize the CO 2 emissions and to meet the future energy requirements by employing fossil fuel reserves.…”

Section: Introductionmentioning

confidence: 99%

Sustainable Hydrates for Enhanced Carbon Dioxide Capture from an Integrated Gasification Combined Cycle in a Fixed Bed Reactor

Hassan

Sher

Fareed

et al. 2021

Ind. Eng. Chem. Res.

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An increase in temperature of up to 2 °C occurs when the amount of CO 2 reaches a range of 450 ppm. The permanent use of mineral oil is closely related to CO 2 emissions. Maintaining the sustainability of fossil fuels and eliminating and reducing CO 2 emissions is possible through carbon capture and storage (CCS) processes. One of the best ways to maintain CCS is hydrate-based gas separation. Selected type T1-5 (0.01 mol % sodium dodecyl sulphate (SDS) + 5.60 mol % tetrahydrofuran (THF), with the help of this silica gel promotion was strongly stimulated. A pressure of 36.5 bar of CO 2 is needed in H 2 O to investigate the CO 2 hydrate formation. Therefore, ethylene glycol monoethyl ether (EGME at 0.10 mol %) along with SDS (0.01 mol %) labeled as T1A-2 was used as an alternative to THF at the comparable working parameters in which CO 2 uptake of 5.45 mmol of CO 2 /g of H 2 O was obtained. Additionally, it was found that with an increase in tetra- n -butyl ammonium bromide (TBAB) supplementation of CO 2 , the hydrate and operating capacity of the process increased. When the bed height was reduced from 3 cm to 2 cm with 0.1 mol % TBAB and 0.01% SDS (labelled as T3-2) in fixed bed reactor (FBR), the outcomes demonstrated a slight expansion in gas supply to 1.54 mmol of CO 2 /g of H 2 O at working states of 283 K and 70 bar. The gas selectivity experiment by using the high-pressure volume analysis through hydrate formation was performed in which the highest CO 2 uptake for the employment of silica contacts with water in fuel gas mixture was observed in the non-IGCC conditions. Thus, two types of reactor configurations are being proposed for changing the process from batch to continuous with the employment of macroporous silica contacts with new consolidated promoters to improve the formation of CO 2 hydrate in the IGCC conditions. Later, much work should be possible on this with an assortment of promoters and specific performance parameters. It was reported in previous work that the repeatability of equilibrium moisture content and gas uptake attained for the sample prepared by the highest rates of stirring was the greatest with the CIs of ±0.34 wt % and ±0.19 mmol of CO 2 /g of H 2 O respectively. This was due to the amount of water occluded inside silica gel pores was not an issue or in other words, vigorous stirring increased the spreadability. The variation of pore size to improve the process can be considered for future work.

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Warming early Mars with climate cycling: The effect of CO2-H2

Cited by 27 publications

References 58 publications

Thermodynamic and Energetic Limits on Continental Silicate Weathering Strongly Impact the Climate and Habitability of Wet, Rocky Worlds

Thermodynamic and Energetic Limits on Continental Silicate Weathering Strongly Impact the Climate and Habitability of Wet, Rocky Worlds

An Energy Balance Model for Rapidly and Synchronously Rotating Terrestrial Planets

Sustainable Hydrates for Enhanced Carbon Dioxide Capture from an Integrated Gasification Combined Cycle in a Fixed Bed Reactor

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