Lecture 10:

Bubbles and PNe

September 26, 2011

III. Conduction Layer- Probe the thermal conduction layer High ions produced by thermal collisions

O VI

N V

C IV

Si IV

UV Probes of the 105 K Gas

C IV N V O VI

Å)1548, 1550 1238, 1242 1031, 1037

Obs. HST STIS HST STIS FUSE

I.P. (eV) 47.9 77.5 138.1

T (K) 1.0105 1.8105 3.0105

Teff (K) >35,000 >75,000 >125,000

Interface of the WR Bubble S308

C IV

Boroson et al. 1997, ApJ, 478, 638

N V

S II

S 308 - ideal for conduction study

HD 50896

* R: H G: [O III] B: X-ray

Boroson et al. (1997) detectedN V absorption from the conduction layer.

HST STIS observation of N Vand C VI emission wasscheduled, but STIS died.

FUSE observations of O VI were awarded, and it died, too.

Spitzer can observe Ne V, but it ran out cryogen.

FUSE Observations of NGC 6543

Gruendl, Chu, Guerrero 2004, ApJL

III. Conduction Layer

- Probe the thermal conduction layer High ions produced by thermal collisions

- NGC 6543: given the boundary conditions of hot interior and warm shell, thermal conduction appears to be consistent, but does not explain the low X-ray luminosity.

Gruendl, Chu, Guerrero 2004, ApJL

Stars and Nebulae: Evolving Together

Steffen & Schönberner (2006)

Stars and Nebulae: Evolving Together

Steffen & Schönberner (2006)

Interacting-Wind Model of PNe

Hot Gas in Planetary Nebulae

Guerrero et al. (2005) Chu et al. (2001) Gruendl et al. (2006)

NGC 2392 NGC 6543 NGC 7026

X-ray emission detected by Chandra & XMM-Newton

Hot Gas in Planetary NebulaeX-ray emission detected by Chandra & XMM-Newton

T = 1-3 x 106 K n 100 cm-3

3.0x106 K2.7x106 K1.7x106 K

To Ensure Detection of Diffuse X-rays

1. Closed shell or lobes to confine hot gas.

2. Stellar winds – P Cygni profiles

3. Nearby, no large extinction

4. OVI, NV lines from interface layer

NGC 246, NGC 3132 - no high ions, no X-rays

High ions and diffuse X-rays fromIC 418, NGC 2392, NGC 6826, NGC 7009

FUSE - Nebular OVI Emission

NGC 7293 (Helix) NGC 6543 (Cat’s Eye)

Stellar P Cygni profile fast stellar wind Nebular O VI emission hot gas from shocked wind

O VI1032

O VI1037

InsideNebula

OutsideNebula

Star

Ly1026

O VI of PNe detected in X-rays

O VI of PNe not detected in X-rays

Pressure-driven bubble with heat conduction at interface

Bubble dynamics does not match

Lx (obs) / Lx (expected) = 10-1 to 10-3

Adjust fast wind- wind velocity- mass loss rate

Reduce heatconduction

Dynamically mix nebular material(mass-loading)

What Next?

Swept-up Shell

Reasonably well understood

Interface (conduction) layer

Spatially-resolved high-dispersion UV spectra are needed

Hot interior

Spatially-resolved high-resolution X-ray spectra are needed