Simulation of gas dynamics and radiation in volcanic plumes on Io

Zhang, J.; Goldstein, David; Varghese, Philip L.; Gimelshein, Natalia; Gimelshein, S. F.; Levin, Deborah A.

doi:10.1016/s0019-1035(03)00050-2

Cited by 79 publications

(51 citation statements)

References 34 publications

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“…The smooth variation in abundance with latitude seen by Jessup et al is difficult to reconcile with volcanic support because volcanic atmospheres are expected to drop off rapidly, on 100 km length scales, away from volcanic sources (Zhang et al 2003).…”

Section: Sublimation Vs Volcanic Support Of the So 2 Atmospherementioning

confidence: 96%

“…The atmosphere is supported by a combination of direct volcanic supply and frost sublimation (Fanale et al 1982, Ingersoll et al 1989, Moreno et al 1991, Wong and Smyth 2000, Zhang et al 2003. The relative roles of the volcanos and the surface frost in directly supporting the atmosphere depend on the frost temperature and the volcanic supply rate, and have not yet been determined.…”

Section: Introductionmentioning

confidence: 99%

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Mid-infrared detection of large longitudinal asymmetries in Io's SO atmosphere

Spencer¹,

Lellouch²,

Richter³

et al. 2005

Icarus

103

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We have observed about 16 absorption lines of the ν 2 SO 2 vibrational band on Io, in disk-integrated 19 µm spectra taken with the TEXES high spectral resolution mid-infrared spectrograph at the NASA Infrared Telescope Facility in November 2001, December 2002, and January 2004 These are the first ground-based infrared observations of Io's sunlit atmosphere, and provide a new window on the atmosphere that allows better longitudinal and temporal monitoring than previous techniques. Dramatic variations in band strength with longitude are seen that are stable over at least a 2 year period. The depth of the strongest feature, a blend of lines centered at 530.42 cm -1 , varies from about 7% near longitude 180 to about 1% near longitude 315 W, as measured at a spectral resolution of 57,000. Interpretation of the spectra requires modeling of surface temperatures and atmospheric density across Io's disk, and the variation in non-LTE ν 2 vibrational temperature with altitude, and depends on the assumed atmospheric and surface temperature structure. About half of Io's 19µm radiation comes from the sun-heated surface, and half from volcanic hot spots with temperatures primarily between 150 and 200 K, which occupy about 8% of the surface. The observations are thus weighted towards the atmosphere over these lowtemperature hot spots. If we assume that the atmosphere over the hot spots is representative of the atmosphere elsewhere, and that the atmospheric density is a function of latitude, the most plausible interpretation of the data is that the equatorial atmospheric column density varies from about 1.5 x 10 17 cm -2 near longitude 180 W to about 1.5 x 10 16 cm -2 near longitude 300 W, roughly consistent with HST UV spectroscopy and Lyman-α imaging. The inferred atmospheric kinetic temperature is less than about 150 K, at least on the anti-Jupiter hemisphere where the bands are strongest, somewhat colder than inferred from HST UV spectroscopy and millimeter-wavelength spectroscopy. This longitudinal variability in atmospheric density correlates with the longitudinal variability in the abundance of optically thick, near-UV bright SO 2 frost. However it is not clear whether the correlation results from volcanic control (regions of large frost abundance result from greater condensation of atmospheric gases supported by more vigorous volcanic activity in these regions) or sublimation control (regions of large frost abundance produce a more extensive atmosphere due to more extensive sublimation). Comparison of data taken in 2001, 2002, and 2004 shows that with the possible exception of longitudes near 180 W between 2001 and 2002, Io's atmospheric density does not appear to decrease as Io recedes from the sun, as would be expected if the atmosphere were supported by the sublimation of surface frost, suggesting that the atmosphere is dominantly supported by direct volcanic supply rather than by frost sublimation. However, other evidence such as the smooth variation in atmospheric abundance with latitude, and atmospheric ch...

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Section: Sublimation Vs Volcanic Support Of the So 2 Atmospherementioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Mid-infrared detection of large longitudinal asymmetries in Io's SO atmosphere

Spencer¹,

Lellouch²,

Richter³

et al. 2005

Icarus

103

View full text Add to dashboard Cite

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“…Detailed plume models are now available (Zhang et al 2003(Zhang et al , 2004, which use a direct simulation Monte Carlo (DSMC) approach and include most of the relevant physical effects for proper modeling of the rarefied nature of the gas flow: vent properties, rotational and vibrational radiation and cooling, ballistics, collisions and shocks, sublimation and condensation, plasma heating. Model parameters are the vent characteristics (vent radius, temperature, density and velocity at the vent), the plasma energy flux, and the surface temperature.…”

Section: Contribution Of Volcanic Plumesmentioning

confidence: 99%

First disk-resolved millimeter observations of Io's surface and SO₂atmosphere

Moullet¹,

Lellouch²,

Moreno³

et al. 2008

A&A

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Aims. In spite of considerable progress in the last two decades, Io's atmosphere remains poorly understood. The goal of this work is to improve our understanding of its spatial distribution, temperature and dynamics. Methods. We present millimeter observations of Io's surface and SO 2 atmosphere at 1.4 mm obtained with the IRAM Plateau de Bure Interferometer in January−February 2005. With a synthesized beam of 0.5 × 1.5 , these observations resolve Io's ∼1.0 disk in the longitudinal / local time direction, and sample the leading and trailing hemispheres of Io. Results. The measured continuum total flux and visibilities show that continuum radiation originates from a depth of at least 1 cm in Io's subsurface. On both the leading and trailing sides, emission in the SO 2 216.643 GHz line appears spatially narrower than the continuum, and suggests that the atmosphere covers ∼80% of the surface on the leading side and ∼60% on the trailing. On the leading side, disk-resolved spectra yield Doppler shift measurements, indicating a beam-integrated limb-to-limb velocity difference of 330 ± 100 m/s in the prograde direction. Such a flow allows an improved fit of disk-averaged SO 2 spectra, but its origin remains to be understood. Mean gas temperatures are in the range 130−180 K, in agreement with estimates from IR measurements, and with a tendency for higher trailing vs leading side gas temperatures. On the basis of realistic plume models, we find that the contribution of isolated volcanic plumes to the SO 2 emission is small.

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“…The presence of spatial variations was confirmed by McGrath et al (2000), where they used spatially resolved HST observations to confirm an atmospheric density enhancement over Pele, a volcanic hotspot, compared to a quiescent location,"T3". This local atmospheric enhancement near volcanic plumes has since been modeled in detail for a variety of plume types (Zhang et al 2003). Currently the exact properties and dominant processes of Io's global atmosphere are still debated.…”

Section: Introductionmentioning

confidence: 99%

Temporal behavior of the SO 1.707 μm ro-vibronic emission band in Io's atmosphere

Laver¹,

Pater²,

Roe³

et al. 2007

Icarus

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We report observations of the ro-vibronic a 1 ∆ → X 3 Σ − transition of SO at 1.707 µm on Io. These data were taken while Io was eclipsed by Jupiter, on four nights between July 2000 and March 2003. We analyze these results in conjunction with a previously published night to investigate the temporal behavior of these emissions. The observations were all conducted using the near-infrared spectrometer NIRSPEC on the W.M. Keck II telescope. The integrated emitted intensity for this band varies from 0.8 x 10 27 to 2.4 x 10 27 photons/sec, with a possible link to variations in Loki's infrared brightness. The band-shapes imply rotational temperatures of 550-1000K for the emitting gas, lending further evidence to a volcanic origin for sulfur monoxide. An attempt to detect the B 1 Σ → X 3 Σ − transition of SO at 0.97 µm was unsuccessful; simultaneous detection with the 1.707 µm band would permit determination of the SO column abundance.

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Simulation of gas dynamics and radiation in volcanic plumes on Io

Cited by 79 publications

References 34 publications

Mid-infrared detection of large longitudinal asymmetries in Io's SO atmosphere

Mid-infrared detection of large longitudinal asymmetries in Io's SO atmosphere

First disk-resolved millimeter observations of Io's surface and SO₂atmosphere

Temporal behavior of the SO 1.707 μm ro-vibronic emission band in Io's atmosphere

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Simulation of gas dynamics and radiation in volcanic plumes on Io

Cited by 79 publications

References 34 publications

Mid-infrared detection of large longitudinal asymmetries in Io's SO atmosphere

Mid-infrared detection of large longitudinal asymmetries in Io's SO atmosphere

First disk-resolved millimeter observations of Io's surface and SO2atmosphere

Temporal behavior of the SO 1.707 μm ro-vibronic emission band in Io's atmosphere

Contact Info

Product

Resources

About

First disk-resolved millimeter observations of Io's surface and SO₂atmosphere