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Beyond the Textbook: Why Planetary Nebula are the Most Exciting Problem in Astrophysics.

Beyond the Textbook: Why Planetary Nebula are the Most Exciting Problem in Astrophysics. Adam Frank University of Rochester. A Cast of Many. Eric Blackman (UR), Orsola De Marco, Bruce Balick. Sean Matt (UV) Jason Nordhaus (UR), T. Dennis (UR) AstroBEAR AMR MHD Andrew Cunningham (UR)

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Beyond the Textbook: Why Planetary Nebula are the Most Exciting Problem in Astrophysics.

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  1. Beyond the Textbook:Why Planetary Nebula are the Most Exciting Problem in Astrophysics. Adam Frank University of Rochester

  2. A Cast of Many Eric Blackman (UR), Orsola De Marco, Bruce Balick Sean Matt (UV) Jason Nordhaus (UR), T. Dennis (UR) AstroBEAR AMR MHD Andrew Cunningham (UR) Kris Yirak (UR)

  3. The Story • PNe are penultimate evolutionary stage of low/intermediate mass stars. • Some view field as mostly “done.” • New observational/theoretical studies show both PNe and late stages of stellar evolution NOT UNDERSTOOD. • New models invoke processes at frontiers of modern astrophysics (magnetic fields, jets, accretion disk) • Strong Lab Astro connection

  4. Stellar and PNe Evolution: The Textbook Picture • AGB -> pPNe-> PNe -> WD • ‘Proven” evolutionary Tracks • Locus of evolution vs. temporal sequence.

  5. White dwarf fast wind sweeps up Red Giant slow wind. Dense shell of snowplowed gas becomes nebula PNe Shapes; Solution circa 1992:Planetary Nebula as Wind Blown Bubbles

  6. Planetary Nebulae: Modern View Narrow Waist Bipolar Outflows Point symmetry Bipolar PNe

  7. Aspherical Bubbles?Generalized Wind Model • Imagine slow wind emerges with a doughnut shape. • “Inertial Confinement” • Fast wind escapes through doughnut holes.

  8. Shaping Starts Early!Aspherical proto-Planetary Nebulae

  9. Multi-Polar Outflows“Young PNe” • T* ~ 30000 K • Ionization fronts just Beginning to break out. • “Starfish” phase

  10. Momentum Excess in pPNeBujarrabal et al 2001 • Outflow shaping begins during proto-PNe stage • Acceleration time short (< 100 y?) • pPNe show pronounced momentum excess! • Radiation driving can not account for outflows

  11. Need a New Paradigm • MHD • Binary Stars

  12. Why MHD for PNe? • Hydrodynamic Models can not recover morphologies. • (Garcia-Segura, Lopez etc) • !! Fields observed in PNe !! • Nebular gas (B ~ mG) • (Miranda et al 2001, Herpin 2004) • Central star (B ~ kG) • (Jordan et al 2004) • Central stars -> hard X-rays • (Kastner et al, Chu et al) PN masers (Miranda et al) PN X-rays ( Chu et al)

  13. MHD and Outflows:Magneto-Rotational Launching (MRL) * GRAND CHALLENGE PROBLEM • MRL -> EVERY COLLIMATED OUTFLOW ENVIRONMENT! • YSOs, AGN, micro-Quasars: GRBs, SNe • Many forms of theory (Blandford & Payne 1985, Shu et al 1994) • Theory/Simulation – “Fling” (Bp) vs. “Spring” (Bf) • Theory of jet launching and collimation • Mature Paradigm – Ex. HH jet rotation -> disk footpoints (Cabrit et al 2006)

  14. MRL Basics Magnetic Tower Models “Spring” (Kato et al) Magneto-centrifugal Models “Fling” (Tsinganos et al) Disk-Star Models (Ferreria et al)

  15. Binary Stars:Common Envelope Evolution • Two (+) evolutionary channels • Mass transfer binary • Merger -> • Rapidly spinning object • 3 Secondary break-up • Disk around primary

  16. Binary Stars Disk & Jets • Link to other Astro systems! • Disks+Jets • Young Stars • AGN • Binary+Jets+Disks • CVs • Micro-quasars

  17. Our Proposal Part 1 • 2 Flavors of MHD Launching • Explosive or Continious

  18. The Tool:AstroBEAR AMR Code Cunningham, Frank, Varniere & Mitran 2007* • “Block” AMR • Choice of solvers/integrators • Parallel – load balance • Multi-physics modules: • Ionization and H2Chemistry • heat conduction • *self-gravity • *rad trans (diff limit) • MHD Flux conservation via CT

  19. Radiative Outflows in Heterogeneous MediaCunningham, Frank, Varniere & Mitran 2007*

  20. MRL Model 1: FlingBlackman, Frank & Welch 01 Both Star and Disk create MRL outflows • Disk forms via disruption of companion • (Soker, Livio, Reyes-Ruiz & Lopez) • Star and Accretion Disk each produce wind (need binary). • Explain multi-polar flows • Scaling Argument fulfills power requirements Energy requirement of Bujarrabal et al 2001

  21. MRL Model 1: Nested Wind SimulationsDennis, Yirak & Frank 2007* (AstroBEAR AMR MHD Code) Slow Inner Wind Fast Inner Wind

  22. MRL Model 1: FlingDetailed Disk Models • Calculate “Full” MRL Disk Solutions • Frank & Blackman 2004 • Disk Around Primary (companion disrupted) • ii) Disk Around Companion Frank & Blackman 04 Garica-Arrendondo & Frank 04

  23. MRL Model 2: SpringBlackman, Frank, Thomas & Van Horn 2001 Nature • Use model (Kawaler) Single Star (!) – • Derive DW(r) profile • Assume MS rotation profile • Evolve via r2W conservation on cylinders • Use calibrated dynamo to calculate field DW -> B2/8p • When AGB “atmosphere” peels off, dynamo field (B = Bf) “unwinds” • Outflow generated with E ~ EpPNe(Bujarrabal)

  24. MRL Model 2: SpringMagnetized Rotating CoresMatt, Frank & Blackman 2004, 2006 • Attempt to simplify and simulate problem. • Initial conditions: • Massive, magnetized ball, initiate rotation t = 0. • W-axis aligned with dipole or monopole • no inflow/outflow • Initially stagnant hydrostatic envelope Mb >> Me

  25. RESULTS: – small scales • DW -> Bf • Bf pressure drives outflow • Bp lines opened

  26. RESULTS : Field Geometry and Morphology Large Scale Small Scale Dipole Field Split Monopole Field

  27. RESULTS: Acceleration and Energetics • Polar and equatorial shells KE dominated, • Polar interior Poynting Flux dominated. (GRBs) • Polar shell exceeds local escape speed after 6 trot

  28. SNe/GRB Magnetic ModelsWheeler et al 2007

  29. pPNe as Explosions: CRL 618 • CRL 618: pPN • “pure” Shock excitation • No photo-ionization • Multiple “lobes” • Jets or Bullets • Hint: “Rings” via vortex shedding.

  30. pPN as ExplositionsBullets vs. Jets: (Dennis, Frank & Balick 2007) • Run 2 and 3D sims of single jet or bullet. • Compare emission maps • Compare PV diagrams • Bullets vortex shedding events match CRL 618 better • Bullet PV diagram better fit as well.

  31. MRL Models and Evolved Stars Conclusion • MRL works for both pPNe and PNe • Rich morphological potential • Tie Star(s) to Nebula

  32. Magnetic Tower Models need Magnetic FieldsOur proposal: Part II Questions: • How do we get magnetic fields in an AGB star?

  33. Dynamo ProblemsCompare Erot with Emag • Dynamos turn DW into B • Dynamo cycle should operate throughout AGB • Need Lmag at end of AGB • Erot << Emag • Don’t have Lmag needed at end of AGB • Need source of differential rotation - binary

  34. Binaries and Dynamos: CE EvolutionNordhaus & Blackman 2006Nordhaus, Blackman & Frank 2006 • Calculate fraction of the orbital energy released by the companion and used for envelope ejection . • Secondary produces drag luminosity. Balance via change in gravitational energy companion. • Calculate end states, W(r) • Use mean field dynamo equations to calculate AGB fields

  35. Dynamos in AGB StarsNordhaus, Blackman & Frank 2006 • No companion Case • Dynamo dies after • t < 50 years • Can maintain with convective reseeding but only with special conditions.

  36. Dynamos in AGB StarsNordhaus, Blackman & Frank 2006 • With Companion Case • CE evolution stirs inner regions. • DW re-supplied. • Magnetic or Thermal Outflow.

  37. Direct Envelope Ejection Outflow is predominately equatorial. Dynamo Driven Ejection Outflow is aligned around the rotation axis and is magnetically collimated. Disk Driven Ejection Shred Secondary Outflow is aligned with rotation axis.

  38. Varniere, Quillen & Frank 2005 D’Alessio et al 2005 HD179821 Disks and pAGB starsNordhaus et al 2007 • “Transitional Disks” with inner holes common in YSOs • Origin: Planets, evaporation • SEDs yield properies • Disks in pAGB stars also appear common • >25% van Winkle et al • pAGB stars SEDs also show holes.

  39. Dynamo Models and Binary Stars Conclusion • Single stars dynamos can’t work • Binary star dynamos can generate needed fields to power explosive outflows

  40. Conclusions • Magneto-rotational models promising for PNe/pPNe. • physics applicable to variety of objects (GRB/SNe, YSOs) • Binary Stars must play critical role. • Accretion disks also likely to be present

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