Alkali and halogen chemistry in volcanic gases on Io

Schaefer, Laura; Fegley, B.

doi:10.1016/j.icarus.2004.08.015

Cited by 33 publications

(27 citation statements)

References 58 publications

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“…Our previous modeling (Schaefer and Fegley, 2005b) showed that SiF 4 can form in Ionian volcanic gases and is the most abundant fluorine-bearing compound at temperatures below ~900 K. In this work, we extend our study of SiF 4 in Ionian volcanic gases in two ways. First, we looked at the change in the SiF 4 /SO 2 ratio of volcanic gases when the F/S ratio is varied.…”

Section: Introductionmentioning

confidence: 59%

“…We modeled chemical equilibria of O, S, Li, Na, K, Rb, Cs, F, Cl, Br, and I compounds as a function of temperature and pressure in an Ionian volcanic gas using the same methods as in our prior work (Schaefer and Fegley, 2005b). We took the nominal temperature and pressure for the Pele volcano as 1760±210 K and 0.01 bars as in our previous models.…”

Section: Chemical Equilibrium Calculationsmentioning

confidence: 99%

“…We took the nominal temperature and pressure for the Pele volcano as 1760±210 K and 0.01 bars as in our previous models. Our nominal elemental composition is listed in Table 1 of Schaefer and Fegley (2005b). We performed two sets of calculations (see Figures 5a and 5f of that paper) both with and without pure condensed SiO 2 (as quartz at low temperatures, and as cristobalite above the quartztcristobalite phase transition temperature at 1079 K; Chase, 1998).…”

Section: Chemical Equilibrium Calculationsmentioning

confidence: 99%

“…The calculated values are compared to SiF 4 /SO 2 ratios observed on Earth (Love et al, 1998;Francis et al, 1996;Mori et al, 2002). Calculations shown in Schaefer and Fegley (2005b) assumed a CI chondritic F/S atomic ratio of 0.00189 (Lodders, 2003). However, terrestrial volcanic rocks typically have F/S atomic ratios much larger than the CI chondritic value (F/S ~ 2 times the CI value in ultramafic rocks, 2-60 times the CI value in basaltic and andesitic rocks, and 10-200 times the CI value in rhyolitic rocks) (Govindaraju, 1994).…”

Section: Chemical Equilibrium Calculationsmentioning

confidence: 99%

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Silicon tetrafluoride on Io

Schaefer

Fegley

2005

Icarus

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Section: Introductionmentioning

confidence: 59%

Section: Chemical Equilibrium Calculationsmentioning

confidence: 99%

Section: Chemical Equilibrium Calculationsmentioning

confidence: 99%

Section: Chemical Equilibrium Calculationsmentioning

confidence: 99%

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Silicon tetrafluoride on Io

Schaefer

Fegley

2005

Icarus

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“…To supply the electron densities observed in the plasma torus, Io ejects mainly S + and O + ions at rates of ≈2×10 28 s −1 (Thomas et al 2004). Besides SO2, millimeter wavelength observations indicate also the presence of Na-, Cl-, and K-bearing volatiles (Schaefer & Fegley 2005). Other elements related to chondritic abundances such as Li, Br, Rb are negligible compared to the above mentioned species (Fegley & Zolotov 2000;Moses et al 2002;Schaefer & Fegley 2005).…”

Section: Io's Volcanic Activitymentioning

confidence: 98%

On the ultraviolet anomalies of the WASP-12 and HD 189733 systems: Trojan satellites as a plasma source

Kislyakova

Pilat-Lohinger

Funk

et al. 2016

Mon. Not. R. Astron. Soc.

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We suggest an additional possible plasma source to explain part of the phenomena observed for the transiting hot Jupiters WASP-12b and HD 189733b in their ultraviolet (UV) light curves. In the proposed scenario, material outgasses from the molten surface of Trojan satellites on tadpole orbits near the Lagrange points L 4 and L 5 . We show that the temperature at the orbital location of WASP-12b is high enough to melt the surface of rocky bodies and to form shallow lava oceans on them. In case of WASP12b, this leads to the release of elements such as Mg and Ca, which are expected to surround the system. The predicted Mg and Ca outgassing rates from two Io-sized WASP-12b Trojans are ≈ 2.2 × 10 27 s −1 and ≈ 2.2 × 10 26 s −1 , respectively. Trojan outgassing can lead to the apparent lack of emission in Mgii h&k and Caii H&K line cores of WASP-12. For HD 189733b, the mechanism is only marginally possible due to the lower temperature. This may be one of the reasons that couldn't explain the early ingress of HD 189733b observed in the far-UV (FUV) Cii doublet due to absence of carbon within elements outgassed by molten lava. We investigate the long-term stability region of WASP-12b and HD 189733b in case of planar and inclined motion of these satellites and show that unlike the classical exomoons orbiting the planet, Io-sized Trojans can be stable for the whole systems life time.

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Solar control of sodium escape from Io

et al. 2014

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We report ground-based spectroscopic observations of the Io sodium cloud before and after eclipse by Jupiter, in a search for possible effects of sunlight on the total atomic sodium content in Io's exosphere. These observations test the importance of the Sun in maintaining the supply of atoms from the thicker atmosphere, which lies close to the surface, to the thinner, more extended, sodium cloud. We performed ground-based spectroscopy of the sodium doublet at 589 nm with a high-resolution échelle spectrograph on the Italian National Telescope Galileo on La Palma Island. We find that the total atomic sodium content immediately after eclipse falls by a factor of~4 during eclipse and recovers to preeclipse values on a timescale of~5 h. We evaluate potential causes of the precipitous drop including condensation of the atmosphere, collapse of the ionosphere, and changes in atmospheric chemistry. We conclude that most plausible cause of the drop in atomic sodium production is the interruption of photodissociation of sodium-bearing molecules during eclipse. We discuss further implications of this change in atmospheric chemistry.

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Alkali and halogen chemistry in volcanic gases on Io

Cited by 33 publications

References 58 publications

Silicon tetrafluoride on Io

Silicon tetrafluoride on Io

On the ultraviolet anomalies of the WASP-12 and HD 189733 systems: Trojan satellites as a plasma source

Solar control of sodium escape from Io

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