ATMOSPHERIC CHEMISTRY IN GIANT PLANETS, BROWN DWARFS, AND LOW-MASS DWARF STARS. III. IRON, MAGNESIUM, AND SILICON

By C. Visscher, K. Lodders, B. Fegley. 2010

135 citations recorded by the source corpus.

We use thermochemical equilibrium calculations to model iron, magnesium, and silicon chemistry in the atmospheres of giant planets, brown dwarfs, extrasolar giant planets (EGPs), and low-mass stars. The behavior of individual Fe-, Mg-, and Si-bearing gases and condensates is determined as a function of temperature, pressure, and metallicity. Our equilibrium results are thus independent of any particular model atmosphere. The condensation of Fe metal strongly affects iron chemistry by efficiently removing Fe-bearing species from the gas phase. Monatomic Fe is the most abundant Fe-bearing gas throughout the atmospheres of EGPs and L dwarfs, and in the deep atmospheres of giant planets and T dwarfs. Mg- and Si-bearing gases are effectively removed from the atmosphere by forsterite (Mg2SiO4) and enstatite (MgSiO3) cloud formation. Monatomic Mg is the dominant magnesium gas throughout the atmospheres of EGPs and L dwarfs and in the deep atmospheres of giant planets and T dwarfs. Silicon monoxide (SiO) is the most abundant Si-bearing gas in the deep atmospheres of brown dwarfs and EGPs, whereas SiH4 is dominant in the deep atmosphere of Jupiter and other gas giant planets. Several other Fe-, Mg-, and Si-bearing gases become increasingly important with decreasing effective temperature. In principle, a number of Fe, Mg, and Si gases are potential tracers of weather or diagnostic of temperature in substellar atmospheres.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/897907cdcb4976968542b03f1cf9b678515e0f49

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In Astronomy and Astrophysics

1. Jon Fortney
2. N. Madhusudhan
3. A. Showman
4. M. Marley
5. V. Parmentier
6. D. Sing
7. M. Line
8. J. D'esert

Citations in the corpus

• Equilibrium chemistry down to 100 K (2017, background): “However, recent kinetic chemical models (Visscher et al. 2006, 2010; Zahnle et al. 2009; Line et al. 2010; Moses et al. 2011; Kopparapu et al. 2012; Venot et al. 2012) have shown that in hot exoplanet atmospheres (T >∼ 1200 K), the chemical timescales are in fact quite short, and hence…”
• NEGLECTED CLOUDS IN T AND Y DWARF ATMOSPHERES (2012, methodology): “…is used to calculate saturation vapor pressures and condensation curves (see Figure 3) for Cr, MnS, Na2S, ZnS, and KCl as a function of pressure, temperature, and metallicity, based upon the mor comprehensive thermochemical models of Lodders & Fegley (see 2.4.1) and Visscher et al. (2006, 2010).”
• The escape of heavy atoms from the ionosphere of HD209458b. I. A photochemical–dynamical model of the thermosphere (2012, background): “The photochemical calculations indicate that,305 in agreement with thermochemical calculations (Visscher et al., 2010), SiO306 is the dominant silicon-bearing gas.”
• HST PanCET Program: A Cloudy Atmosphere for the Promising JWST Target WASP-101b (2017, methodology): “We approximate the condensate cloud forming species from multiple condensation curves from Visscher et al. (2010), Morley et al. (2012), and Wakeford et al. (2017).”
• QUANTITATIVELY ASSESSING THE ROLE OF CLOUDS IN THE TRANSMISSION SPECTRUM OF GJ 1214b (2013, methodology): “…silicate and iron clouds condense in L dwarfs (e.g. Tsuji et al. 1996; Allard et al. 2001; Marley et al. 2002; Burrows et al. 2006; Cushing et al. 2008; Visscher et al. 2010) and sulfide and chloride clouds condense in T dwarfs (Lodders & Fegley 2006; Visscher et al. 2006; Morley et al. 2012).”
• A chemical model for the atmosphere of hot Jupiters (2012, background): “Deviations from the thermodynamic equilibrium have been discussed with timescale arguments (e.g. Lodders & Fegley 2002; Fortney et al. 2006, 2008b; Visscher et al. 2006, 2010; Madhusudhan & Seager 2010) or modeled with a few reactions describing the CO-CH4 conversion coupled with the dynamics…”
• TRANSITIONS IN THE CLOUD COMPOSITION OF HOT JUPITERS (2016, methodology): “We then calculate the lightcurves assuming the same metal enrichment to determine the opacities, the abundances of cloud-forming material and the condensation curves for MnS and MgSiO3 clouds (Morley et al. 2012; Visscher et al. 2010).”
• DISEQUILIBRIUM CARBON, OXYGEN, AND NITROGEN CHEMISTRY IN THE ATMOSPHERES OF HD 189733b AND HD 209458b (2011, methodology): “…of both theoretical and experimental data for channel R860 was the motivating factor for the present ab initio transition-state theory analysis, as Visscher et al. (2010b) have suggested that this pathway could be important in the overall interconversion scheme between CH4 and CO on giant planets.”
• Observing the Atmospheres of Known Temperate Earth-sized Planets with JWST (2017, methodology): “We use the Chemical Equilibrium with Applications model (CEA, Gordon & McBride 1994) to compute the thermochemical equilibrium molecular mixing ratios (with applications to exoplanets see, Line et al. 2010; Visscher et al. 2010; Line et al. 2011; Moses et al. 2011; Line & Yung 2013).”
• From thermal dissociation to condensation in the atmospheres of ultra hot Jupiters: WASP-121b in context (2018, methodology): “As in previous thermochemical grid models (see Lodders & Fegley 2002; Visscher et al. 2006, 2010), molecular species thermally dissociate at high temperatures and low pressures via net thermochemical reactions such as H2 2H H2O 2H+O TiO Ti+O VO V+O, 1 We define the azimuth as the projected angle…”