Planetesimal Capture by an Evolving Jupiter
Planetesimal Capture by an Evolving Jupiter
Planetesimal Capture by an Evolving Jupiter
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Motivation• Gravitational perturbation of (growing) <strong>Jupiter</strong>scatters out pl<strong>an</strong>etesimals in it vicinityIf <strong>Jupiter</strong> was originally of solar composition, it wouldstay with the same composition• Abund<strong>an</strong>ce of high Z material in <strong>Jupiter</strong> is severaltimes larger th<strong>an</strong> solar (consistent with atmosphericmeasurements with Galileo)??
Gi<strong>an</strong>t Pl<strong>an</strong>et FormationDisk InstabilityCore accretion
<strong>Jupiter</strong>-massclump0.5 AUIncreasing temp.& densityHelled, Podolak, Kovetz (2006)
-Two-body system- Uniform distributionof pl<strong>an</strong>etesimals1km-V = 1 km/s- No interaction withProto-<strong>Jupiter</strong>Mass (gr)10km-No pl<strong>an</strong>etesimal isejected.100kmTime (years)Helled, Podolak, Kovetz (2006)
• <strong>Jupiter</strong>-mass envelope/clump• Initial radius = 0.5 AU• Duration of contraction = 2.71 x 10 5 years0.5 AUIncreasing temp.& density
271000 (yr)Temperature (K)48900 (yr)9030 (yr)3120 (yr)0.140.270.400.53Dist<strong>an</strong>ce (AU)
• 3600 <strong>Pl<strong>an</strong>etesimal</strong>• Size = 1, 10, 100 km• Density = 2.8 g/cm -3(ice+rock)3.7 AU Σ = r -3/26.6 AU
MineralsRock (Silicate)Ice
3.7 AU Σ = r -3/26.6 AU
Gas DragF Drag= C D12 " a 2 # v 2C D is the drag coefficient which depends on theKnudsen number, the Reynolds number, <strong>an</strong>d theMach number. !Aerodynamic Heating1E D= "!v2I = C D /2 in the limit of large Knudsen number, <strong>an</strong>din the limit of supersonic flow (for a cap of shockheatedgas). We assume this is approximately trueeverywhere.3
Dynamical Breakup1Pdyn = ! v22(Ram Pressure)If this pressure exceeds thecompressional strength of thematerial it will fracture unlessheld together <strong>by</strong> self-gravity.a=5v2dyn8!"2b"G
• Aerodynamic heatingHeating• Radiation from ambient atmosphere1E D= "!v2E = !4atmT atm3Cooling• Radiative cooling• Evaporative coolingE = !E4radT surfvap=qPvap( Tsurf)µ2!N kTAsurf
3.7 AU Σ = r -3/26.6 AU
8E+126E+124E+122E+12PLAN0220100km0E00-2E+12-4E+12PLAN0975100kmPLAN097610km-6E+12-8E+12
100km
100km10km
100km10km1km
100km10km1km
Radius Loss (km)Time (yr)
1= 3.73 - 3.98 5= 4.73 - 4.98 9= 5.73 - 5.982= 3.98 - 4.23 6= 4.98 - 5.23 10= 5.98 - 6.233= 4.23 - 4.48 7= 5.23 - 5.48 11= 6.23 - 6.484= 4.48 - 4.73 8= 5.48 - 5.73 12= 6.48 - 6.66# <strong>Pl<strong>an</strong>etesimal</strong>sZone (AU)
Conclusions <strong>an</strong>d Future Work- Smaller pl<strong>an</strong>etesimals are captured in shorter times- Multiple passages of larger pl<strong>an</strong>etesimals through theenvelope results in more capture <strong>an</strong>d more mass deposit- Nebular gas/pl<strong>an</strong>etesimals interaction will be included- Accumulation of high density pl<strong>an</strong>etesimals aroundgas-pressure structures in the envelope enh<strong>an</strong>ces the rateof the capture of these objects.Stay Tuned
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