1. Hot Gas in Planetary Nebulae You-Hua Chu Robert A. Gruendl Martín A. Guerrero Univ. of Illinois

2. Hot Gas Expected in Interacting Winds Fast wind is shocked to 10 7 - 10 8 K Hot gas in bubble interior 10 6 K Conduction layer 10 5 K

3. Complications and Problems Fast stellar wind - isotropic? collimated? - constant velocity? - constant mass loss rate? Mixing with nebular gas - thermal evaporation - dynamic ablation - presence of magnetic field Non-equilibrium ionization - abundance, temperature, mass

4. When we can’t get potatos, we eat yams… (massive star bubbles)

5. Interstellar and Circumstellar Bubbles Low-mass   RG, AGB  CSPN Slow wind Fast wind   Circumstellar Circumstellar nebula bubble Interstellar bubble    Slow wind Fast wind Massive   RSG, LBV  WR 

6. Circumstellar Bubble NGC 6888

7. Chandra X-ray Image of NGC 6888 R: H  G: [O III] B: X-ray Gruendl, Guerrero, Chu 2003, in prep.

8. Circumstellar Bubble S308

9. XMM-Newton X-ray Image of S 308 HD 50896 * R: H  G: [O III] B: X-ray Chu et al. 2003, submitted

10. X-ray Spectra of Hot Gas in WR Bubbles NGC 6888 (Chandra) S 308 (XMM)

11. X-ray Observations of Shocked Fast Wind Detection of hot gas associated with fast winds - 6 PNe, 2 WR bubbles, 2 superbubbles* Properties of the hot gas: T e [10 6 K ] N e [cm -3 ] L X [erg/s] PN 2-3  10 6 100 10 31  10 32 WR 1-2  10 6 1 10 34 SB 8  10 6 0.1 10 33 (* Townsley et al. 2003, ApJ, in press - Rosette & Omega)

12. Pressure-driven bubble with heat conduction at interface L x (obs) / L x (expected) = 10 -1 to 10 -3  Adjust fast wind - wind velocity - mass loss rate  Reduce heat conduction Dynamically mix nebular material  More observations are needed.

13. and potato skins… (10 5 K gas at the interface)

14. FUSE - Nebular OVI Absorption IC 418NGC 2392 Stellar P Cygni profile; nebular O VI absorption HH HH 1037 1032 1037 1032

15. FUSE - Nebular OVI Emission NGC 7009NGC 6543 Stellar P Cygni profile; nebular O VI emission Inside Outside Star 1032 1037

16. FUSE - Nebular OVI Emission NGC 7293 NGC 3132 No stellar P Cygni profile; No nebular O VI emission 1037 1032 O I C II Star Inside

17. Hot gas is cool !!!

18. Future Obs of the “Interface” in S308 HD 50896 * XMM-Newton observation, mapping the whole shell CTIO 4m echelle obs of H  & [O III] lines of the 10 4 K gas FUSE observations of O VI emission from 3 positions HST STIS observations of N V and C IV emission (will propose again…)