A parametric study of Io’s thermophysical surface properties and subsequent numerical atmospheric simulations based on the best fit parameters

Walker, Andrew; Moore, Chris H.; Goldstein, David; Varghese, Philip L.; Trafton, Laurence M.

doi:10.1016/j.icarus.2012.05.001

Cited by 36 publications

(35 citation statements)

References 26 publications

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“…Feaga et al, 2009;Feldman et al, 2000). However, these results do not corroborate the simulations published by Walker et al (2012) which predict a more rapid fall off in the equatorial SO 2 gas density from the afternoon peak to the morning terminator (Fig. 14C), when the atmosphere is supported by SO 2 frost with albedo P0.55, and thermal inertia <200 J m À2 K À1 s À1/2 (hereafter, MKS).…”

Section: Zero-latitude So 2 Gas Density Correlations With Time Of Daycontrasting

confidence: 59%

“…Assuming that the atmosphere is sublimation supported, all of the Ly-a and NUV observations require high ($300 MKS or greater) frost thermal inertia values to replicate the substantial SO 2 gas density detected along the terminators in those observations (cf. Strobel and Wolven, 2001;Feaga et al, 2009;Walker et al, 2012). Likewise, as discussed above the seasonal variability indicated by both the NUV and mid-IR observations is best replicated by thermal inertial values greater than 300 MKS, for average SO 2 bond albedo values $0.5.…”

Section: Frost Properties Derived From Multi-spectral Atmospheric Andmentioning

confidence: 52%

“…However, panel (B) shows that when identical longitudes are compared, a decrease in the gas density (corresponding to $0.6 K decrease in frost temperature) from morning to late afternoon is implied. In panel (C) the results derived from the 2011 observations are compared with model results derived by Walker et al (2012) for the anti-jovian hemisphere assuming that the subsolar-longitude (sslong) is 195W, and the thermal inertia $200 MKS; the Walker et al model predicts a change in gas density with time of day that is much faster than what is inferred from our observations. region there are multiple locations that are rich in SO 2 with lower albedo values (ranging from 0.52 to $0.4); additionally, as Fig.…”

Section: Zero-latitude So 2 Gas Density Correlations With Time Of Daymentioning

confidence: 78%

“…The 0.55 minimum SO 2 frost albedo adopted by Walker et al (2012) was based on (i) the correlation of SO 2 rich regions with high bolometric albedo values, based on the analysis of Galileo NIMS and SSI data, completed by Douté et al (2001) and Simonelli et al (2001), respectively, and (ii) the assumption that any variance in the observed average surface bolometric albedo (which is a function of both SO 2 and non-SO 2 components) is solely a function of changes in the relative fractional coverage of the SO 2 and non-SO 2 frost components. However, in Io's low latitude The inferred zero-latitude gas density is plotted as a function of time of day in panels (A and B), revealing that the inferred zero-latitude SO 2 gas densities fall into two nearly parallel lines when plotted vs. time of day in Io hours.…”

Section: Zero-latitude So 2 Gas Density Correlations With Time Of Daymentioning

confidence: 99%

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Spatially resolved HST/STIS observations of Io’s dayside equatorial atmosphere

Jessup

Spencer

2015

Icarus

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Section: Zero-latitude So 2 Gas Density Correlations With Time Of Daycontrasting

confidence: 59%

Section: Frost Properties Derived From Multi-spectral Atmospheric Andmentioning

confidence: 52%

Section: Zero-latitude So 2 Gas Density Correlations With Time Of Daymentioning

confidence: 78%

Section: Zero-latitude So 2 Gas Density Correlations With Time Of Daymentioning

confidence: 99%

See 2 more Smart Citations

Spatially resolved HST/STIS observations of Io’s dayside equatorial atmosphere

Jessup

Spencer

2015

Icarus

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“…Both approaches are important and complementary. The first approach is taken by the recent paper by Walker et al (2012) (see also Walker, 2012), while the present paper is devoted to the second approach with special attention paid to the effect of the noncondensable gas.…”

Section: Introductionmentioning

confidence: 99%

Unsteady flows in Io’s atmosphere caused by condensation and sublimation during and after eclipse: Numerical study based on a model Boltzmann equation

Kosuge¹,

Aoki²,

Inoue³

et al. 2012

Icarus

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a b s t r a c tThe behavior of Io's atmosphere during and after eclipse is investigated on the basis of kinetic theory. The atmosphere is mainly composed of sulfur dioxide (SO 2 ) gas, which condenses to or sublimates from the frost of SO 2 on the surface depending on the variation of surface temperature ($90-114 K). The atmosphere may also contain a noncondensable gas, such as sulfur monoxide (SO) or oxygen (O 2 ), as a minor component. In the present study, an accurate numerical analysis for a model Boltzmann equation by a finite-difference method is performed for a one-dimensional atmosphere, and the detailed structure of unsteady gas flows caused by the phase transition of SO 2 is clarified. For instance, the following scenario is obtained. The condensation of SO 2 on the surface, starting when eclipse begins, gives rise to a downward flow of the atmosphere. The falling atmosphere then bounces upward when colliding with the lower atmosphere but soon falls again. This process of falling and bounce back of the atmosphere repeats during the eclipse, resulting in a temporal oscillation of the macroscopic quantities, such as the velocity and temperature, at a fixed altitude. For a pure SO 2 atmosphere, the amplitude of the oscillation is large because of a fast downward flow, but the oscillation decays rapidly. In contrast, for a mixture, the downward flow is slow because the noncondensable gas adjacent to the surface hinders the condensation of SO 2 . The oscillation in this case is weak but lasts much longer than in the case of pure SO 2 . The present paper is complementary to the work by Moore et al. (Moore, C.H., Goldstein, D.B., Varghese, P.L., Trafton, L.M., Stewart, B. [2009]. Icarus 201, 585-597) using the direct simulation Monte Carlo (DSMC) method.

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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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A parametric study of Io’s thermophysical surface properties and subsequent numerical atmospheric simulations based on the best fit parameters

Cited by 36 publications

References 26 publications

Spatially resolved HST/STIS observations of Io’s dayside equatorial atmosphere

Spatially resolved HST/STIS observations of Io’s dayside equatorial atmosphere

Unsteady flows in Io’s atmosphere caused by condensation and sublimation during and after eclipse: Numerical study based on a model Boltzmann equation

Solar control of sodium escape from Io

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