1 / 43

The Chemical Composition of the Sun and Friends

The Chemical Composition of the Sun and Friends. C. Allende Prieto The University of Texas at Austin. Contents. How to? 1- model atmospheres 2- spectrum formation (opacities, NLTE,…) 3- coverage, resolution, S/N, analysis What for? The Forseeable Desirable Future.

misty
Download Presentation

The Chemical Composition of the Sun and Friends

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. The Chemical Composition of the Sun and Friends C. Allende Prieto The University of Texas at Austin

  2. Contents • How to? 1- model atmospheres 2- spectrum formation (opacities, NLTE,…) 3- coverage, resolution, S/N, analysis • What for? • The Forseeable Desirable Future

  3. 1 Model atmospheres • Hot photospheres (Teff> 15000 K): NLTE, winds, blanketing

  4. Line blanketed- NLTE Model photospheres O-star grid Lanz & Hubeny 2003

  5. Lanz & Hubeny 2003

  6. Lanz & Hubeny 2003 Vs. Kurucz 1993

  7. 1 Model atmospheres • Hot photospheres (Teff> 15000 K): NLTE, winds, blanketing • Cool photospheres (4500 < Teff < 15000 K) : line blanketing, surface inhomogeneities

  8. image from SDAC at NASA GSFC

  9. Movie by P. Brandt (KIS), G. Scharmer (Stockholm), G. W. Simon (Sunspot), N. Hoekzema (Utrech), W. Muhlmann (Graz) and R. Shine (Palo Alto) from the SVST at the ORM on the island of La Palma

  10. 3D simulation of surface convection B. Freytag & M. Steffen

  11. 1 Model atmospheres • Hot photospheres (Teff> 15000 K): NLTE, winds, blanketing • Cool photospheres (4500 < Teff < 15000 K) : line blanketing, surface inhomogeneities • Cooler photospheres (Teff< 4500 K): molecular opacities, dust/cloud formation

  12. Burrows, Sudarsky & Hubeny 2005

  13. Burrows, Sudarsky & Hubeny 2005

  14. 2 Spectral line formation • UV Atomic continuum opacities

  15. Allende Prieto, Hubeny & Lambert 2003

  16. 2 Spectral line formation • UV Atomic continuum opacities • Line absorption coefficients: damping wings

  17. Barklem et al. 2003

  18. 2 Spectral line formation • UV Atomic continuum opacities • Line absorption coefficients: damping wings • Atomic and molecular line data

  19. Lawler, Sneden & Cowan 2004

  20. 2 Spectral line formation • UV Atomic continuum opacities • Line absorption coefficients: damping wings • Atomic and molecular line data • NLTE

  21. Na I in the Solar Spectrum Allende Prieto, Hubeny & Lambert 2003

  22. 3 Observation/Analysis • Ø, Coverage, multiplexing, R

  23. 3 Observation/Analysis • Data Reduction • Analysis: From Ews to line profiles • Neural networks, genetic algorithms and other optimization schemes

  24. What for?The Golden Rule The Surface Composition of a star reflects that of the ISM at theTime the star formed

  25. Golden rule applies? yes • Galactic structure and chemical evolution

  26. SDSS DR3

  27. Radial gradients Allende Prieto et al. 2006

  28. Golden rule applies? yes • Galactic structure and chemical evolution • Solar Structure

  29. Golden rule applies? yes • Galactic structure and chemical evolution • Solar Structure • Cosmology: 1H, 2H, 3He, 4He, 7Li, 6Li

  30. BBN Figure from Edward L. Wright

  31. Golden rule applies? yes • Galactic structure and chemical evolution • Solar Structure • Cosmology: 1H, 2H, 3He, 4He, 7Li, 6Li • SN yields

  32. R-process is universal Sneden et al. 2003

  33. Golden rule applies? NO • Difusion (Sun, CPs, accretion, SN yields again)

  34. Secondary stars in BH/NS binary systems Centaurus X-4 Gonzalez-Hernandez et al. 2005

  35. Golden rule applies? NO • Difusion (Sun [M/H]-0.07 dex, CPs, accretion, SN yields again) • Mixing and destruction (Li, Be)

  36. Golden rule applies? NO • Difusion (Sun [M/H]-0.07 dex, CPs, accretion, SN yields again) • Mixing and destruction (Li, Be) • RV Tauri stars

  37. Giridhar et al. 2005

  38. Recent trends • 3D model atmospheres: a beginning • full NLTE: good progress for hot stars, but … • Data archival: survey projects going on with massive archives that become public (low-res: SDSS, SEGUE, GALEX) (high-res: Elodie, S4N) • Analysis automation: a beginning • Breaking the Z barrier

  39. The Desirable future • 3D model atmospheres • full NLTE • A pending observational test for solar-type stars: center-to-limb variation of the solar spectrum • Data archival: VOs (including both observations and models) • Stronger efforts to measure/compute atomic data • Stronger efforts to use the newly available atomic data • Full analysis automation • R – an ignored variable?

  40. ? B-type F-type M-type

  41. ---- 12 ---- 18 ---- 15cm

More Related