Jets, Outflows, Bullets and Clumps in Astrophysics

1
Jets, Outflows, Bullets and Clumps in
Astrophysics

• Adam Frank
• University of Rochester/LLE
• A. Poludnenko, A. Cunningham, T. Gardiner,
  S.Sublett,
• Jim Knauer, Tim Collins, Igumenshchev, E.
  Blackman, D. Meyerhofer, R. Betti, S. Skupsky

2
Jets/Pulsed Flows Problem Definition

• Collimated Outflows from central source
• Ubiquitous Phenomena
• Astrophysical Fossils
• Imprint reveals source physics (Dt L/V)
• Most outflows show spatial variability
• intensity variations, knots, multiple bow shocks
• Big Q. Is Variability intrinsic to source?

3
Pulsed/Outflow Environments

• Young Stars V 400 km/s, L 1 ly
• Evolved Low Mass Stars V 102 - 103 km/s, L
  1 ly
• (M lt 8 Mo)
• Evolved High Mass Stars V 500 km/s, L 1 ly
  
• Compact Objects V c, L 1 ly
• (BH, NS)
• AGN V c, L 1000 ly

4
Jets Young Stellar Objects

• Star formation collapsing cloud accretion
  disk
• Disk launches jet via magneto-centrifugal forces
• Disk instabilities drive pulsing?

5
Pulsed Outflows YSOs

• Timescales
• tshort 10 y
• tbs 500 y
• HH212
• Reflection symmetry

6
Star Formation Jets
7
Real Astronomical Movies Herbig Haro 111 2 HST
images a few years apart
8
HH 111 jet
9

Real Astronomical Movies HH 1/2
10
HH 1/2
11
HH 1 jet
12
HH 1 jet
13
HH 1
14
HH 1
15
HH 2
16
HH 2
17

• Outflows not always look like
• jets
• Sometimes irregular or clumpy

S106 star forming region in Cygnus (Subaru
telescope)
18
(No Transcript)
19
Evolved stars - Planetary Nebulae

• Late stages of evolution for Solar-type stars
• Planetary Nebulae interacting stellar winds
• Slow dense AGB wind -gt Fast tenuous PN wind

20
Planetary Nebulae
21
Planetary Nebulae
He 3 1475 Conical Converging Flows And X-rays
22
Planetary Nebulae
CRL 618 Bullets PNe?
23
Jets vs Interstellar Bullets

• BEARCLAW -gt Rochester Adaptive Mesh Refinement
  code
• A. Poludnenko, P. Varnie, A. Cunningham

24
Pulsing Magnetic Field Effects

• Helical Fields combed out

Mach 20, b 100 Jet (Gardiner Frank 2000)
Bp
Bf
25
Magnetic Field Effects

• Jets/outflows likely to be magnetized
• Toroidal fields exert PINCH forces

Mach 10, b 1 Jet (Frank et al 1998)
B Bff
26
Wind Blown BubblesInertial Confinement

• Wind expands into ambient torus.
• 3 discontinuities
• ambient wind shocks
• Contact Disc.
• Shocks elongated

27
Fast Winds overtake to Slow OnesWind Blown
Bubbles

• White dwarfs fast wind sweeps up Red Giants
  slow wind.

• Dense shell of snowplowed gas becomes visible
  nebula

28
What about the Aspherical Bubbles?

• Imagine slow wind emerges with a doughnut shape.
• Could occur via binary companion.
• Fast wind escapes through doughnut holes.

29
Paradigms Found?Magnetic Fields

• Magnetic Fields are common in astrophysics.
• Field lines like rubber bands.
• Imagine fast wind with magnetic hoops.

30
Bubbles, Jets Magnetic Fields

• Fields link Molecular Outflows and Jets?

31
Clumpy Flows

• Flows in inhomogeneous (clumpy) media are
  common
• May be affected by mass-loading processes
• Mixing, turbulence, shock propagation

• Planetary Nebulae (e.g. NGC 7293, NGC 2392)
• Wolf-Rayet nebulae (e.g. RCW 58)
• Supernova remnants (e.g. Cygnus Loop)
• Regions of low-mass star formation (e.g.
  Trapezium cluster, HH regions)
• Molecular clouds

32
(No Transcript)
33
The Physics of Clumpy Flows (in a box)
Poludnenko, Frank Blackman 2002
AMRCLAW based adaptive mesh refinement
Mach 10.0 shock wave interacting with a system of
3 identical clouds, density contrast 500.0,
adiabatic regime, shown is logarithmic density
34
The Physics of Clumpy Flows (in a box)
Poludnenko, Frank Blackman 2002
Mach 10.0 shock wave interacting with a system of
14 identical clouds, density contrast 500.0,
adiabatic regime, shown is logarithmic density
35
Clumpy Flows Characterizing the System
Mixing
Note Do not see mass loading! Clumps disperse
first (cooling? Mellema et al 2002)
36
Clumpy Flows Characterizing the System

• What Matters (build on Klein et al 2002)
• thickness of the clump system as opposed to the
  total clump mass
• clump distribution in the system as opposed to
  the total number of clumps

Quantitative characteristics of clumpy systems

• Clump destruction length LCD, distance traveled
  by a clump prior to its breakup

These two parameters distinguish between
interacting and noninteracting regimes of clump
system evolution
37
Application 1 Clumpy Flows (in the lab)
Poludnenko et al 2002
Clumpy Cloud experiment design for HEDLA

• Realistic clump volume fraction
• OK clump/ambient medium density ratio (40)
• Reasonably steady shock
• Strong enough shock convert clumps to plasma

38
Simulating the Experiment (Large N system)

• Mach 10 steady shock
• System of 200 clumps
• Density contrast ? 40
• Clump radius 25 ?m
• Domain size 3 x 4 mm

39
Clumpy Flows (in the lab) Poludnenko et al 2002

• What you can see.
• OK clump/ambient medium density ratio (40)
• Reasonably steady shock
• Strong enough shock convert clumps to plasma

40
Conclusions

• Outflow systems good place to do our work
• Smooth, pulsed, clumpy all interesting
• Need high mach numbers.
• Need radiation losses.
• Need magnetic fields.
• Pure clumpy flow systems also interesting