Resolving Enceladus Plume Production Along the Fractures. Ben Southworth, Sascha Kempf 13 Aug., PDF Free Download

Resolving Enceladus Plume Production Along the Fractures Ben Southworth, Sascha Kempf 13 Aug., 217

New results

New results (not 5kg/s)

New results (not 5kg/s) More large particles

New results (not 5kg/s) More large particles Temporal variability

New results (not 5kg/s) More large particles Temporal variability More questions than answers

Outline Plumes - what, where and why? Resolving mass production Implications on particle distributions and tilted jets

W 9 W Alexandria Damascus Cairo Baghdad 27 W 18 W

CH4 and N2 fraction in plume gas High Old Faithful Cold Faithful Plume Which Type? one? Frigid Faithful Frigid Faithful Deep Source Deep Source Ice plume stratification Strong

Plume Model Deep source particle speed distribution taken from Schmidt et al. (28): p(v r) 1 8 6 4 r=.1um r=.2um r=.6um r=1um r=3um 2.1.2.3.4 Velocity (km/s).5.6.7

Plume Model Deep source particle speed distribution taken from Schmidt et al. (28): Size distribution follows power law with slope α

Plume Model Deep source particle speed distribution taken from Schmidt et al. (28): Size distribution follows power law with slope α Assume particles ejected azimuthally uniform

Plume Model Deep source particle speed distribution taken from Schmidt et al. (28): Size distribution follows power law with slope α Assume particles ejected azimuthally uniform Assume polar ejection angle follows cos 2 - distribution

Equations of motion Accounts for planet s gravity and second moment, moon s gravity, and particle charging.

Equations of motion Accounts for planet s gravity and second moment, moon s gravity, and particle charging. > Simulate millions of particles

Equations of motion Accounts for planet s gravity and second moment, moon s gravity, and particle charging. > Simulate millions of particles Create quasi-steady state model of plume

Equations of motion Accounts for planet s gravity and second moment, moon s gravity, and particle charging. > Simulate millions of particles Create quasi-steady state model of plume Create impact rate profile on surface of moon

Outline Plumes - what, where and why? Resolving mass production Implications on particle distributions and tilted jets

Two low-altitude flybys E7 W E21 W C/A 2s C/A 1s C/A 1s 9 W C/A 27 W 9 W C/A 27 W Damascus Damascus C/A+2s C/A+1s Alexandria Cairo Baghdad C/A+1s Alexandria Cairo Baghdad 18 W C/A+2s 18 W. 1.5 3. 4.5 5.9 7.4 8.9. 11.5 22.9 34.4 45.9 57.4 68.8 Number Density of Grains >1.7µm (m -3 ) Number Density of Grains >1.6µm (m -3 )

E7 flyby Altitude to Enceladus (km) 3 25 2 15 125 1 1 125 15 2 25 3 4 r>1.7μm 3 2 Impact rate (particles/sec) 1 8 6 4 2 1 8 6 4 r>3.μm r>6.5μm M + = 25 kg/s, α = 2.8 M + = 25 kg/s, α = 3.1 CDA impact rate 2 7:41 7:42 7:43 Spacecraft time: 21, day 12

E21 flyby 2 15 1 75 5 5 75 1 125 175 225 3 r >1.6μm 2 Altitude to Enceladus (km) 1 Impact rate (particles/sec) 8 6 4 2 1 8 6 4 r >2.7μm r >6.μm 2 15:22: 15:22:2 15:22:4 15:23: Spacecraft time: 215, day 31 All jets, M + =25kg/s CDA impact rate 15:23:2

What happened in E21? Altitude to Enceladus (km) 3 25 2 15 125 1 1 125 15 2 25 3 4 r>1.7μm 3 9 W E21 C/A 49 km C/A 15s 74 km W E7 C/A 99 km C/A 2s 13 km 27 W Impact rate (particles/sec) 2 1 8 6 4 2 1 8 6 4 r>3.μm r>6.5μm M + = 25 kg/s, α = 2.8 M + = 25 kg/s, α = 3.1 CDA impact rate 2 7:41 7:42 7:43 2 15 1 75 5 5 75 1 125 175 225 3 r >1.6μm 2 1 74 km C/A+15s 131 km C/A+2s 18 W Impact rate (particles/sec) 8 6 4 2 1 8 6 4 r >2.7μm r >6.μm 2 15:22: 15:22:2 15:22:4 15:23: Spacecraft time: 215, day 31 All jets, M + =25kg/s CDA impact rate 15:23:2

Temporal variation Altitude to Enceladus (km) 3 25 2 15 125 1 1 125 15 2 25 3 4 r>1.7μm 3 9 W E21 C/A 49 km C/A 15s 74 km W E7 C/A 99 km C/A 2s 13 km 27 W Impact rate (particles/sec) 2 1 8 6 4 2 1 8 6 4 r>3.μm r>6.5μm M + = 25 kg/s, α = 2.8 M + = 25 kg/s, α = 3.1 CDA impact rate 2 7:41 7:42 7:43 2 15 1 75 5 5 75 1 125 175 225 3 r >1.6μm 2 1 74 km C/A+15s 131 km C/A+2s 18 W Impact rate (particles/sec) 8 6 4 2 1 8 6 4 r >2.7μm r >6.μm 2 15:22: 15:22:2 15:22:4 15:23: Spacecraft time: 215, day 31 All jets, M + =25kg/s CDA impact rate 15:23:2

Impact rate (particles/sec) 2 15 1 75 5 5 75 1 125 175 225 3 r>1.6μm 2 1 8 6 4 2 1 8 6 4 r>2.7μm Altitude to Enceladus (km) r>6.μm M + = 25 kg/s, α = 2.8 M + = 25 kg/s, α = 3.1 CDA impact rate 2 15:22: 15:22:2 15:22:4 15:23: Spacecraft time: 215, day 31 15:23:2 Impact rate (particles/sec) 3 25 2 15 125 1 1 125 15 2 25 3 4 r>1.7μm 3 2 1 8 6 4 2 1 8 6 4 r>3.μm r>6.5μm Altitude to Enceladus (km) M + = 25 kg/s, α = 2.8 M + = 25 kg/s, α = 3.1 CDA impact rate 2 7:41 7:42 7:43 Spacecraft time: 21, day 12

Outline Plumes - what, where and why? Resolving mass production Implications on particle distributions and tilted jets

Size distribution Simulated size-distribution slope C/A 15s 74 km W Size-distribution slope as measured by CDA C/A 15s 74 km W 5 C/A 2s 13 km C/A 2s 13 km 4.5 9 W C/A 49 km C/A 99 km 27 W 9 W C/A 49 km C/A 99 km 27 W 4 74 km C/A+15s 74 km C/A+15s 131 km C/A+2s 18 W 131 km C/A+2s 18 W 3.5

Speed vs. size distribution

Speed vs. size distribution 7 Monte Carlo weights Size distribution slope at CA 6 5 4 3 2 1 1 2 3 4 5 6 7 Altitude at CA (km) 1 2 3 4 5 6 7 Altitude at CA (km)

Thank you for your attention! [1] B. S. Southworth, S. Kempf, and J. N. Spitale. Surface Deposition of the Enceladus Plume and the Angle of Emissions. Icarus (submitted).

Outline Plumes - what, where and why? Resolving mass production Implications on particle distributions and tilted jets

Why surface deposition?

Why surface deposition? (1) How long have plumes been active?

Why surface deposition? (1) How long have plumes been active? (2) Have the same plumes always been active?

Why surface deposition? (1) How long have plumes been active? (2) Have the same plumes always been active? (3) Where are plumes active?

Why surface deposition? (1) How long have plumes been active? (2) Have the same plumes always been active? (3) Where are plumes active? (4) What is the plume emission structure?

Competing theories of emissions

Competing theories of emissions Jets ~1 discrete jets proposed in Porco et al. (214). Provide location and angle with respect to surface.

Competing theories of emissions Jets ~1 discrete jets proposed in Porco et al. (214). Provide location and angle with respect to surface. Curtain Joseph Spitale suggested some jets formed in Porco et al. are phantom jets. Instead, plume is mostly a curtain.

Color maps Enceladus Colour Map 9 3 Colour Map -9 9 IR/UV Map -9 36 18 Schenk et al., GRL, subm.

9 9 Color maps Simulation Matches Data Enceladus Colour Map 3Simulation Colour Map -9-9 9 log IR/UV Map IR/UV Map -9 36 Mass deposition dominated by south pole sources 18 Schenk et al., GRL, subm.

Jets vs. curtains log IR/UV Map 9 Jets Curtain 9 36 W 18 W W 36 W 18 W W 1-1 1-2 1-3 1-4 1-5 1-6 Ice Deposition (mm/yr)

Effects of tilted jets log IR/UV Map 9 Jet 23 Jet 95 9 36 W 18 W W 36 W 18 W W 1-1 1-2 1-3 1-4 1-5 1-6 Ice Deposition (mm/yr)

Effects of tilted jets log IR/UV Map 9 All jets Jet zenith < 3º Jet zenith < 2º 9 36 W 18 W W36 W 18 W W 36 W 18 W W 1-6 1-5 1-4 1-3 1-2 Ice Deposition (mm/yr) 1-1

Resolving Enceladus Plume Production Along the Fractures. Ben Southworth, Sascha Kempf 13 Aug., 2017