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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 10 5 K Gas. C IV N V O VI - PowerPoint PPT Presentation
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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