1 / 41

Grains and Gas in the Ejecta of Classical Novae

Grains and Gas in the Ejecta of Classical Novae. R. D. Gehrz Department of Astronomy, University of Minnesota. Outline. Novae and Galactic chemical evolution Outburst Development Physical properties of nova grains Gas Phase abundances Comparisons with ISM and the Solar System Grains

tocho
Télécharger la présentation

Grains and Gas in the Ejecta of Classical Novae

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Grains and Gas in the Ejecta of Classical Novae R. D. Gehrz Department of Astronomy, University of Minnesota R. D. Gehrz

  2. Outline • Novae and Galactic chemical evolution • Outburst Development • Physical properties of nova grains • Gas Phase abundances • Comparisons with ISM and the Solar System Grains • Summary R. D. Gehrz

  3. A Classical Nova Explosion: Accretion followed by a TNR R. D. Gehrz

  4. The Role of Classical Novae in Galactic Chemical Evolution R. D. Gehrz

  5. Stardust and Stellar Evolution R. D. Gehrz

  6. The luminosity of the outburst fireball is Lo LEdd • c measures nH and the ejected ionized gas mass Mgas during the free-free expansion phase (10-4 M) • Lo LEdd = LIR for optically thick dust shells  Lo = constant for a long time Fireball Expansion Phase IR/Radio Development Phases Free-Free Expansion Phase Coronal Phase in ONeMg Novae Dust Cocoon Phase in CO Novae  in m R. D. Gehrz (1988, 1990) R. D. Gehrz

  7. Physical Parameters Derivable from IR SED’s and Spectra TBB in K and time of the outburst to in JD for expanding photospheres and dust shells The apparent luminosity; for blackbodies, f = 1.36 ( f )max in W cm-2 The free-free self-absorption wavelength c in m The outflow velocity Vo in Km s-1 from emission lines R. D. Gehrz

  8. Mass of the Ejecta from IR SED’s in M in M From Thomson scattering, which dominates the shell opacity during the fireball/free-free transition: From c during the optically thin free-free phase: Mgas  1-3x10-4 M for ONeMg WD’s Mgas  1-5x10-5 M for CO WD’s These methods are independent of D as long as Vo is known from IR spectra R. D. Gehrz

  9. Dust Formation in NQ Vul • Tc 1000 K • , where Vo is the • outflow velocity Visual Transition  Dust Condensation in CO Novae Lo LEdd = LIR Tc = 1000K R. D. Gehrz (1988, 1990) R. D. Gehrz

  10. IR Spectra of Dust Grains: Molecular Structure • Silicates: SiO2 bond stretching and bending • vibrational mode emission at 10 m and 20 m • Silicon Carbide: SiC stretching vibrational mode • emission at 11.3 m • Carbon and iron: Smooth emissivity • Hydrocarbons (HAC and PAH): C-H stretch at 3.3 m and • other stretching modes at longer wavelengths R. D. Gehrz

  11. Nova Grain Properties Novae produce carbon, SiC, silicates, and hydrocarbons Abundances can be derived from visual opacity, IR opacity, and IR emission feature strength The grains grow to radii of 0.2-0.7m R. D. Gehrz

  12. Amorphous Carbon Grains in the Ejecta of NQ Vul, LW Ser, and V1668 Cyg Gehrz 1988, ARA&A, 26, 377 Iron seems not to be an option based on abundance arguments Gehrz et al. 1984, ApJ, 281, 303 R. D. Gehrz

  13. Carbon and SiC Grains in Nova 1370 Aql (1982) Data from Gehrz et al. 1984, ApJ, 281, 303 R. D. Gehrz

  14. Grain Condensation in V842 Cen (1986) • Amorphous Carbon • Hydrocarbons • Silicates From R. D. Gehrz, 1990, in Physics of Classical Novae, eds. A. Cassatella and R. Viotti, Springer-Verlag: Berlin, p. 138. R. D. Gehrz

  15. Grain Condensation in Nova QV Vul 1987 (2) • Carbon, Silicates, SiC, and PAH grains formed at different epochs • suggesting abundance gradients in the ejecta. • A. D. Scott (MNRAS, 313, 775-782 (2000)) has shown that this could • be explained by an asymmetric ejection due to a TNR on a rotating WD R. D. Gehrz

  16. Grain Condensation in V705 Cas (1993) • s Free-free, amorphous carbon, silicates, and hydrocarbon UIR emission are required to fit the IR spectrum in detail. There are many variables – constraining data are needed R. D. Gehrz

  17. Modeling the IR SED of V705 Cas (1993) There are many variables – constraining data are needed See C. Mason et al. 1998, ApJ, 494, 783 R. D. Gehrz

  18. Grain Mass, Abundance, and Size in M compared to solar abundance Mdust from the infrared luminosity of the dust shell: Abundance of the grain condensables is given by: Grain radius from the optical depth of the visual transition and LIR: in m (agr 0.2-0.7m) R. D. Gehrz

  19. Hydrocarbon Dust in Two Recent Novae R. D. Gehrz

  20. Comets as the “Rosetta Stone” of the Solar System • They are the remaining “planetesimals” from the epoch of planet formation in the primitive Solar nebula • The material released from comet nuclei during perihelion passage is therefore a sample of the content of this primordial environment • IR imaging photometry and spectroscopy can be used to deduce the composition and physical properties of the gas, dust, and ices present when the planets were forming R. D. Gehrz

  21. SOFIA and Comets: Mineral Grains What can SOFIA observations of comets tell us about the origin of the Solar System? ISO Data • Comet dust mineralogy: amorphous, crystalline, and organic constituents • Comparisons with IDPs and meteorites • Comparisons with Stardust • Only SOFIA can make these observations near perihelion Spitzer Data The vertical lines mark features of crystalline Mg-rich crystalline olivine (forsterite) R. D. Gehrz

  22. Comet Grain Properties R. D. Gehrz

  23. agr  0.7m agr  0.2m Comet Hale-Bopp Comet Dust and Nova Dust Compared r = 1.21 AU  TBB = 253K • Both Comet dust and nova dust contain silicates and carbon • Comets have coma emission dominated by grains the size of those produced in nova outflows R. D. Gehrz

  24. IDP’s are composed of sub micron grains within a “Cluster of Grapes” fractal structure tens to hundreds of microns across • IDP sub- grains are similar in structure, size, and composition to nova “stardust” • IDP’s have Carbon, Silicate, and hydrocarbon components seen in nova grains Novae and the Primitive Solar System: Interplanetary Dust Particles (IDPs) R. D. Gehrz

  25. On the Nature of the Dust in the Debris Disk around HD 69830C. M. Lisse, C. A. Beichman, G. Bryden, and M. C. Wyatt The Astrophysical Journal, 658:584–592, 2007 March 20 Using a robust approach to determine the bulk average mineralogical composition of the dust, we show it to be substantially different from that found for comets 9P/Tempel 1 and C/ Hale-Bopp 1995 O1 or for the comet-dominated YSO HD 100546.Lacking in carbonaceous and ferrous materials but including small icy grains, the composition of the HD 69830 dust most closely resembles that of a disrupted P- or D-type asteroid. R. D. Gehrz

  26. Abundances from IR Forbidden Emission Lines Greenhouse et al. 1988, AJ, 95, 172 Gehrz et al. 1985, ApJ, 298, L47 Hayward et al. 1996, ApJ, 469, 854 R. D. Gehrz

  27. SOFIA and Classical Nova Explosions What can SOFIA tell us about gas phase abundances in Classical Nova Explosions? • Gas phase abundances of CNOMgNeAl • Contributions to ISM clouds and the primitive Solar System • Kinematics of the Ejection R. D. Gehrz

  28. Abundance Anomalies in “Neon” Novae ONeMg TNR’s can produce and excavate isotopes of CNO, Ne, Na, Mg, Al, Si, Ca, Ar, and S, etc. that are expelled in their ejecta ONeMg TNR’s are predicted to have highly enhanced 22Na and 26Al abundances in their outflows. These isotopes are implicated in the production of the 22Ne (Ne-E) and 26Mg abundance anomalies in Solar System meteoritic inclusions : 22Ne via: 22Na  22Ne + e + +  (1/2 = 2.7 yr) 26Mg via: 26Al  26Mg + e + +  (1/2 = 7105 yr) R. D. Gehrz

  29. Classical Novae and Abundance Anomalies • Novae process  0.3% of the ISM • (dM/dt)novae 7x10-3 M yr-1 • (dM/dt)supernovae 6x10-2 M yr-1 Gehrz, Truran, and Williams 1993 (PPIII, p. 75) and Gehrz, Truran, Williams, and Starrfield 1997 (PASP, 110, 3) have concluded that novae may affect ISM abundances: Novae may be important on a global Galactic scale if they produce isotopic abundances that are  10 times SN and  100 times Solar; Ejected Masses calculated from IR/Radio methods give a lower limit R. D. Gehrz

  30. Chemical Abundances in Classical Novae from IR Data (1) R. D. Gehrz

  31. Chemical Abundances in Classical Novae from IR Data (2) R. D. Gehrz

  32. Chemical Abundances in Classical Novae from IR Data (3) R. D. Gehrz

  33. 20Ne/22Ne (Solar Wind) = 13.9 0.60 0.50 0.40 0.30 0.20 0.10 0.00 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 - Normal GSC IDPs Anomalous GSC IDPs Normal IDPs Normal TTC IDPs Anomalous TTC IDPs 22Ne (10-3 cm3STP g-1 IDP) Anomalous IDPs 20Ne (10-3 cm3STP g-1 IDP) -

  34. 20Ne/22Ne (Solar Wind) = 13.9 0.60 0.50 0.40 0.30 0.20 0.10 0.00 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 - Normal GSC IDPs Anomalous GSC IDPs Normal IDPs Normal TTC IDPs Anomalous TTC IDPs 22Ne (10-3 cm3STP g-1 IDP) Anomalous IDPs 20Ne (10-3 cm3STP g-1 IDP) -

  35. 104 103 102 101 100 10-1 10-2 10-3 10-4  Neon Nova Neon Novae range 10-5 SN II range <10-8 Solar Wind  20Ne/22Ne  20Ne/21Ne  4He/20Ne Isotope Ratios  21Ne/22Ne 3He/4He 

  36. 104 103 102 101 100 10-1 10-2 10-3 10-4  Neon Nova Neon Novae range 10-5 SN II range <10-8 Solar Wind  20Ne/22Ne  20Ne/21Ne  4He/20Ne Isotope Ratios  21Ne/22Ne 3He/4He 

  37. 104 103 102 101 100 10-1 10-2 10-3 10-4 Anomalous IDPs  Neon Nova 10-5 Neon Novae range Solar Wind Normal IDPs  20Ne/21Ne   20Ne/22Ne 21Ne/22Ne Isotope Ratios 4He/20Ne  3He/4He  3He nd <10-8

  38. 104 103 102 101 100 10-1 10-2 10-3 10-4 Anomalous IDPs  Neon Nova 10-5 Neon Novae range Solar Wind Normal IDPs  20Ne/21Ne   20Ne/22Ne 21Ne/22Ne Isotope Ratios 4He/20Ne  3He/4He  3He nd <10-8

  39. Summary and Conclusions IR/Radio data yield quantitative estimates for physical parameters characterizing the nova outburst: D , Lo , Mgas , Tdust , adust , Mdust , Vo , Lo , grain composition, and elemental abundances Nova ejecta produce all known types of astrophysical grains: amorphous carbon, SiC, hydrocarbons, and silicates Classical Nova ejecta have large overabundances (factors of 10 to 100) of CNO, Ne, Mg, Al, S, Si R. D. Gehrz

  40. Summary and Conclusions: Pre-Solar Clouds IR/Radio data show that the mineral composition and size distribution of the “stardust” made by novae are similar to those of the small grains released by comets in the Solar System IR/Radio data confirms theoretical predictions suggesting that nova TNRs can produce ejecta that lead to 22Ne (Ne-E) and 26Mg enhancements such as are seen in meteorites Novae are therefore a potential source for at least some of the solids that were present in the primitive Solar Nebula R. D. Gehrz

  41. Future Research Physical parameters and abundances must be obtained for a larger sample of novae to improve statistics Observations of stellar populations in M33 will be conducted using SIRTF to understand the global galactic contributions of classical novae Further examination of IDPs and meteoritic inclusions should be made to identify pre-solar grains from novae R. D. Gehrz

More Related