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Gas and Dust Layers from Cassiopeia A’s Explosive Nucleosynthesis

Gas and Dust Layers from Cassiopeia A’s Explosive Nucleosynthesis. L. Rudnick, University of Minnesota JINA Feb 2008. The work of many experts…. SPITZER T. DeLaney, MIT J. Ennis, U MN T. Kozasa, Hokkaido H. Morgan, Cardiff W. Reach, Spitzer J. Rho, Spitzer J.D. Smith, U. Toledo.

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Gas and Dust Layers from Cassiopeia A’s Explosive Nucleosynthesis

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  1. Gas and Dust Layers fromCassiopeia A’sExplosive Nucleosynthesis L. Rudnick, University of Minnesota JINA Feb 2008

  2. The work of many experts… SPITZER T. DeLaney, MIT J. Ennis, U MN T. Kozasa, Hokkaido H. Morgan, Cardiff W. Reach, Spitzer J. Rho, Spitzer J.D. Smith, U. Toledo RADIO, X-RAY, OPTICAL R. Petre, U. Hwang, GSFC R. Fesen (Dartmouth) J. Bowden (Colorado Coll.) N. Kassim (Naval RL) Funding: NASA (Chandra/HST/Spitzer) and NSF (radio)

  3. Distance ~3.4 kpc • Size ~ 5 pc • Explosion energy ~ 1-2x1051 erg • Initial velocities ~ 1.5x104 km/s • Compact remnant – neutron star, (AXP, SGR?) ~2 MO • Progenitor mass 15-25 MO WR ? Binary?

  4. Key Questions • What is the shape of the explosion? • What is the fate of the nucleosynthesis layers? • What is the mass and composition of new dust? • What is the future?

  5. • Messages to take home • Until now, the ONLY ejecta which have been seen in Cas A (optical, IR, X-ray, radio) are those that have just crossed the reverse shock • The explosion of the inner layers was flattened. with multiple “jets”  different nucleosynthesis layers are now visible in each direction. • Dust becomes visible at the reverse shock, with different compositions from different layers • The currently visible dust mass is 0.02-0.05 MO, with even more still in the interior? •

  6. EXPLOSIONSTRUCTURE Outer and reverse shocks

  7. EXPLOSIONSTRUCTURE Multiple temperature overlapping plasmas 104K relativistic 107K 102K

  8. EXPLOSIONSTRUCTURE Proper Motions optical X-ray (~radio)

  9. EXPLOSIONSTRUCTURE A paradox – optical, X-ray, radio

  10. Resolving the explosion paradox –separate X-ray spectral components High energy cont. Iron. Silicon. Low energy

  11. Resolving the paradox - matching components X-ray (total) OXYGEN X-ray O Optical O X-ray Si Optical Si SILICON

  12. Individual features – same velocity opt, radio, Xray Velocity distributions different in each band X-ray (total) X-ray O Optical O X-ray Si Optical Si SILICON

  13. EXPLOSIONSTRUCTURE New view of the explosion

  14. EXPLOSIONSTRUCTURE • The motion of material is different than the motion of the shock – • Ejecta become visible as they encounter the reverse shock Milliseconds seconds into the explosion

  15. Spitzer Infrared Telescope

  16. Spitzer – what can it see?

  17. EXPLOSIONSTRUCTURE Doppler 3D structure Argon Silicon

  18. The Explosion in 3-D

  19. EXPLOSIONSTRUCTURE • The explosion of the outer layers was spherical, setting up forward and reverse shocks. • The explosion of the inner layers has a flattened (pancake) structure • “Fingers” or jets of material protrude in the plane separating the layers

  20. NUCLEOSYNTHESIS LAYERS INTEGRAL High energy X-rays 44Ti 44Sc44Ca Renaud et al., ApJ L ‘07

  21. NUCLEOSYNTHESIS LAYERS Astro-ph/0712.1071 Incomplete Si-burning Explosive O-burning Circumstellar Complete Si-burning Chandra X-ray spectroscopy

  22. NUCLEOSYNTHESIS LAYERS As the fingers/jets cross the reverse shock and become visible, the nucleosynthesis layers remain intact

  23. NUCLEOSYNTHESIS LAYERS Neon “moons” – ionized gas variations Different layers in the gas Ne-rich layers OIV X-ray Si GAP

  24. DUST TYPE & MASS Different layers in the dust

  25. DUST TYPE & MASS Dust – compositions Circumstellar Small carbon grains, PAH? Deep layers Si, Ar, S + dust: SiO2, FeO, MgSiO3 Intermediate layers: Ne, O + dust: Al2O3

  26. DUST TYPE & MASS Dust Composition - closer look Deep, O-burning Intermed., C-burning Al2O3 proto-silicate peak

  27. DUST TYPE & MASS Dust Mass Distributions Deep, O-burning Intermed., C-burning

  28. . 0.02 < Mdust/MO < 0.054 CSM Silicates C-products DUST TYPE & MASS Ejecta dust mass…total visible… Expectations for production, e.g., Nozawa et al. 2003 up to ~1 MO Low end of requirement for dust seen in the early universe, BUT, destruction should also be very important!

  29. Uncertainties DUST TYPE & MASS Very cold ejecta dust? or ISM from foreground CO clouds? How to fit 70mic 21 70 13CO 850m How much dust has not yet reached reverse shock?

  30. FUTURE How much more to come? Si XIV Si II

  31. HST Reverse shock Continuing evolution – reaching the reverse shock

  32. Messages to take home • Until now, the ONLY ejecta which have been seen in Cas A (optical, IR, X-ray, radio) are those that have just crossed the reverse shock • The explosion of the inner layers was flattened. with multiple “jets”  different nucleosynthesis layers are now visible in each direction. • Dust becomes visible at the reverse shock, with different compositions from different layers • The currently visible dust mass is 0.02-0.05 MO, how much more still in the interior? .

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