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Automated Fitting of High-Resolution Spectra of HAeBe stars

Automated Fitting of High-Resolution Spectra of HAeBe stars. Improving fundamental parameters Jason Grunhut Queen’s University/RMC. Motivation. Common ways to determine temperature Photometry SED Problems Extinction/emission and calibrations Many corrections necessary

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Automated Fitting of High-Resolution Spectra of HAeBe stars

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  1. Automated Fitting of High-Resolution Spectra of HAeBe stars Improving fundamental parameters Jason Grunhut Queen’s University/RMC

  2. Motivation • Common ways to determine temperature • Photometry • SED • Problems • Extinction/emission and calibrations • Many corrections necessary • Take advantage of high-res ESPaDOnS spectra • Minimal corrections required

  3. Full ESPaDOnS Spectral Range 11000 K synthetic model

  4. Full ESPaDOnS Spectral Range 11000 K synthetic model

  5. Spectrum variation with temperature from nearest Kurucz models (±500 K)

  6. Spectrum variation with temperature from nearest Kurucz models (±500 K)

  7. Automated Fitting of Spectra • Search through a pre-defined grid of synthetic spectra. • 4200-5200 Angstroms • Solar abundances. • Most current VALD line list. • Micro-turbulent velocity of 2 km/s. • No macro-turbulence. • Models computed using synth3 • Grid from 6500-35000 K, log(g) from 3.0-5.0 • 100 K resolution up to 20000 K, 200 K resolution from then up.

  8. How Program Works • Radial velocity is first determined based on suggested model. • Projected rotational velocity is fit for each model in the specified range (computed using slightly modified s3dIV code). • Model with minimum chi-square represents best fit. • Radial velocity is fit for a final time for best model.

  9. Theoretical Results for 11000 K synthetic model with vsini of 40 km/s CLEAR MINIMUM EXISTS

  10. Chi-Square MapHD 17081 • Using chi-square map, can estimate uncertainties. • Using 3 parameter fitting space, chi-square difference of 21.1 represents a formal 99.99% confidence level. • closest model has greater than 2300 chi-square difference

  11. Theoretical Results • Investigated • SNR • vsini • varying Fe abundance • random noise to log(gf) values • micro/macro turbulence • binaries • normalization • conclusion • other than binaries, for reasonable variations, ~100-200 K uncertainties

  12. Results

  13. HD 17081 • B7IV Classification • Best Fit • 13700 K • Log(g)=4.0 • vsini=20 km/s • Literature Results • ~12300 K

  14. HD 17081

  15. HD 17081

  16. HD 17081 Balmer Fits Best Fit: 11800 K, Log(g)=3.5 Best Fit: 12000 K, Log(g)=4.0

  17. HD 34282 • A0e+sh Classification • Best Fit • 10200 K • Log(g)=4.5 • vsini=108 km/s • Literature Results • ~8700 (+410,-198) K

  18. HD 34282

  19. HD 34282 Balmer Fits Best Fit: 9800 K, Log(g)=4.5 Best Fit: 10100 K, Log(g)=4.5

  20. HD 36112 • A8e Classification • Best Fit • 7900 K • Log(g)=4.0 • vsini=52 km/s • Literature Results • ~7700 K

  21. HD 36112

  22. HD 36112 Balmer Fits Best Fit: 8000 K, Log(g)=5.0 Best Fit: 8100 K, Log(g)=5.0

  23. HD 31648 • A3pshe+ Classification • Best Fit • 8200 K • Log(g)=3.5 • vsini=95 km/s • Literature Results • 8700 K • 9250 K, Log(g)=3.5

  24. HD 31648

  25. Difficult Stars:BF Ori • A5II-IIIe var • Best Fit • ~7500 • Log(g)~4.0 • vsini~53 km/s • Literature Results • 6750

  26. BF Ori

  27. HR DIAGRAM:New Temperatures

  28. HR Diagram:New Temperatures and Distances

  29. HR Diagram:New Temperatures and Computed Photometry

  30. FUTURE WORK • Automated fitting for all field HAeBe stars with ESPaDOnS observations. • Use improved temperatures to improve mass and age estimates. • Use Bayesian statistical approach to improving luminosities. Major Issues • Abundances for chemically peculiar stars. • Micro/macro turbulence. • Systematic normalization issues.

  31. THE END

  32. Balmer Line Normalization: HD36112

  33. Balmer Line Normalization: HD139614

  34. Balmer Line Normalization:Comparison between ESPaDOnS and FORS1 HD 36112

  35. Uncertainty vs SNRFor 15000 K synthetic model with 40 km/s vsini.

  36. 15000 K synthetic model with 40 km/s vsini

  37. Difficult stars:HD 31293

  38. HD 31293

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