Liquid water on Enceladus from observations of ammonia and 40Ar in the plume

Waite, J. H.; Lewis, William S.; Magee, B.; Lunine, Jonathan I.; McKinnon, William B.; Glein, Christopher R.; Mousis, O.; Young, D. T.; Brockwell, T.; Westlake, J. H.; Nguyen, M.-J.; Teolis, B. D.; Niemann, H. B.; McNutt, R. L.; Perry, Mark; Ip, W.-H.

doi:10.1038/nature08153

Cited by 482 publications

(496 citation statements)

References 29 publications

Supporting

Mentioning

482

Contrasting

Unclassified

Order By: Relevance

“…This was measured to be 2.9 +1.5 −0.7 × 10 −4 (Waite et al 2009), which is very close to the value found for OCCs (see Fig. 4), and serves as the most useful tool currently available for evaluating the formation of Enceladus.…”

Section: Enceladussupporting

confidence: 52%

“…While each of these measurements provides insight into the evolution of Titan's atmosphere, the most important values for evaluating Titan's formation are the three that have been determined to represent primordial composition of the building blocks of Titan (italicized in Table 4). The D/H in water at Titan can be presumed to be in the same range as Xe/N Xe < 5 × 10 −9c -2 .58 × 10 −6d was determined for Enceladus (Waite et al 2009;Mousis et al 2009a). The limited range of values for primordial D/H in methane is based on limits placed by the evolution of 12 C/ 13 C in Titan's methane (Mandt et al 2009(Mandt et al , 2012, while the upper limit for 14 N/ 15 N in Titan's nitrogen inventory is based on the maximum possible fractionation allowed due to escape processes (Mandt et al 2014).…”

Section: Enceladusmentioning

confidence: 99%

See 1 more Smart Citation

Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites

et al. 2015

Self Cite

View full text Add to dashboard Cite

Comets play a dual role in understanding the formation and evolution of the solar system. First, the composition of comets provides information about the origin of the giant planets and their moons because comets formed early and their composition is not expected to have evolved significantly since formation. They, therefore serve as a record of conditions during the early stages of solar system formation. Once comets had formed, their orbits were perturbed allowing them to travel into the inner solar system and impact the planets. In this way they contributed to the volatile inventory of planetary atmospheres. We review here how knowledge of comet composition up to the time of the Rosetta mission has contributed to understanding the formation processes of the giant planets, their moons and small icy bodies in the solar system. We also discuss how comets contributed to the volatile inventories of the giant and terrestrial planets.

show abstract

Section: Enceladussupporting

confidence: 52%

Section: Enceladusmentioning

confidence: 99%

Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…[46] As described in the works of Teolis et al [2010] and Waite et al [2009], the spikes in the H 2 signal (Figure 9) during IM67 are due to ice-grain impacts. The ice grain impact releases H 2 , which travels through the instrument in 3-4 ms, and produces an enhanced H 2 signal in a single IP.…”

Section: H 2 and Evidence Of Ice Grainsmentioning

confidence: 99%

“…Careful examination of Enceladus plume data [Waite et al, 2009] shows that velocitydependent dissociative products of H 2 O and CO 2 dominate channels 2 and 28, respectively. The ionization process generates H 2 from H 2 O and CO from CO 2 at a rate of a few percent, but the flight data show that high ram velocities cause dissociation at much higher rates.…”

Section: Additional Inms Signals and The Vertical Distribution Of Thementioning

confidence: 99%

See 1 more Smart Citation

Cassini INMS observations of neutral molecules in Saturn's E‐ring

et al. 2010

View full text Add to dashboard Cite

[1] In 2008, the Cassini ion neutral mass spectrometer (INMS) investigation made in situ measurements of neutral species near Saturn's equatorial plane within 0.5 Saturn radii (R S ) of the orbit of Enceladus. After removing the large background and modeling to interpret instrumental effects, the data provide rough constraints on the neutral distribution and composition. These data show an azimuthal asymmetry in the neutral densities and provide measurements used to compare to simulations of neutral H 2 O emitted from Enceladus. Far from Enceladus, the neutral water densities, at a few times 10 3 molecules/cm 3 , are near the detection limit of INMS. Near Enceladus, but outside of the plumes and north of the equatorial plane, the INMS detects particles within 5000 km of Enceladus, with the density increasing to approximately 10 5 molecules/cm 3 at the equatorial plane. The observations also show CO 2 in the form of its dissociated product, CO. On the basis of the spatial distribution of CO 2 counts, the scale height of the neutral cloud above and below the equatorial plane is less than 7000 km. Far from Enceladus, the concentration of CO 2 with respect to H 2 O increases, a consequence of the predicted decline in H 2 O density. Relatively high counts at 2 amu are infrequently observed. These measurements indicate H 2 released during ice-grain impacts and provide a constraint on the frequency and distribution of small ice grains.

show abstract

The effect of an asymmetric core on convection in Enceladus' ice shell: Implications for south polar tectonics and heat flux

Showman

Han

Hubbard

2013

Geophysical Research Letters

View full text Add to dashboard Cite

[1] Enceladus exhibits a strong tectonic contrast between its south polar terrain (SPT), which is young and geologically active, and its northern hemisphere, which is relatively ancient and stable. Previous global three-dimensional (3-D) spherical models of convection exhibit patterns that are symmetrical around the equator and fail to explain the formation of a hemispheric dichotomy. Here we present global 3-D spherical models of convection in Enceladus' ice shell to show that convection in Enceladus' ice shell with plasticity and irregular core geometry can self-consistently generate a hemispheric dichotomy in tectonics and heat flux. With a spherical core, convection produces global overturning, which cannot explain the regional confinement of Enceladus' current tectonic activity to the SPT. Models with appropriate nonspherical core geometry and plasticity tend to produce overturning confined to the SPT or regional overturning in different regions at different times, which can explain the tectonic dichotomy and local age differences on Enceladus. Our models predict heat flows up to 5-10 gigawattts (GW) during active episodes, consistent with Cassini observations. Citation: Showman, A. P., L. Han, and W. B. Hubbard (2013), The effect of an asymmetric core on convection in Enceladus' ice shell: Implications for south polar tectonics and heat flux, Geophys. Res. Lett., 40,[5610][5611][5612][5613][5614]

show abstract

Liquid water on Enceladus from observations of ammonia and 40Ar in the plume

Cited by 482 publications

References 29 publications

Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites

Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites

Cassini INMS observations of neutral molecules in Saturn's E‐ring

The effect of an asymmetric core on convection in Enceladus' ice shell: Implications for south polar tectonics and heat flux

Contact Info

Product

Resources

About