The Last Hurrah: pPN Formation by a Magnetic Explosion Sean Matt 1 Adam Frank 2 & Eric Blackman 2 1 McMaster U. ; 2 U. of Rochester August 1, 2003 APN3: Crystal Mountain WA Structured Outflows from Single, Evolved Stars

The Missing Link?

Some Key Observations pPNe: P >> L/c (Knapp 1986; Bujarrabal et al. 2001) Often V w  r (e.g., Cat’s Eye, Reed et al. 1999; Rotten Egg, Alcolea et al. 2001) t acc < t ppn (e.g., Bujarrabal et al. 2001) Needed: New wind acceleration mechanism (not radiation) that is: Triggered at end of AGB phase Self-shaped Explosive AGB wind spherical, yet pPNe are not (e.g., Terzian & Hajian 2000) Sahai & Trauger (1996)

Core-Envelope Interaction Core Envelope cc BB Magnetic Force At end of AGB: Envelope driven off Differential Rotation Magnetic Dynamo Blackman et al. (2001):

Hydrostatic Envelope “Solid” Core Dipole Field MHD Sims: Parameters: V esc, V rot, V A

If we assume: M core = 0.5 M sun V esc = 1000 km/s M Egg ≈ M sun (Bujarrabal et al. 2001) R Egg ≈ 10 4 AU Some “real” #’s: Then: R core ≈ 0.2 R sun B core ≈ 10 5 Gauss KE core ≈ erg T spin-down ≈ 100 years Thompson, Hines, & Sahai (1997) ??

 B Dipole Parameter Space Split Monopole

Conclusions Magnetic Explosion Mechanism Explains: P >> L/c and V  r WD’s rotate slowly (e.g., Koester et al. 1998) New physics! --> More applications Open Questions: What is trigger? --> detailed stellar evolution! Large scale propagation --> must include spin-down 3 Dimensions --> will produce more structure