Automated Fitting of High-Resolution Spectra of HAeBe stars

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Automated Fitting of High-Resolution Spectra of
HAeBe stars

• Improving fundamental parameters
• Jason Grunhut
• Queens University/RMC

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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

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Full ESPaDOnS Spectral Range 11000 K synthetic
model
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Full ESPaDOnS Spectral Range 11000 K synthetic
model
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Spectrum variation with temperature from nearest
Kurucz models (500 K)
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Spectrum variation with temperature from nearest
Kurucz models (500 K)
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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.

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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.

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

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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

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Results
Name Metallic Lines (Teff, Log(g)) Reduced ?2 H? (Teff, Log(g)) Hß (Teff, Log(g)) Literature Value
HD 142666 7700, 4.0 6.68 7300, 3.5 7500, 4.5 8500
HD 144432 7700, 4.0 7.16 7200, 3.0 7400, 4.5 7950
HD 17081 13700, 4.0 6.21 11800, 3.5 12000, 4.0 12300
HD 244604 8600, 3.5 5.29 8200, 4.0 8100, 4.0 9500
HD 31648 8200, 3.5 25.77 8300, 4.0 8300, 4.0 8700 1005
HD 34282 10200, 4.5 2.23 9800, 4.5 10100, 4.5 8700 410/-198
HD 35187 9200, 4.0 4.66 8700, 4.0 8600, 4.0 9100 420
HD 36112 7900, 4.0 5.36 8000, 5.0 8100, 5.0 7750 358
HD 53367 31200, 4.5 3.61 29200, 4.0 31400, 4.0 31600 3650
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HD 17081

• B7IV Classification
• Best Fit
• 13700 K
• Log(g)4.0
• vsini20 km/s
• Literature Results
• 12300 K

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HD 17081
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HD 17081
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HD 17081 Balmer Fits
Best Fit 11800 K, Log(g)3.5
Best Fit 12000 K, Log(g)4.0
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HD 34282

• A0esh Classification
• Best Fit
• 10200 K
• Log(g)4.5
• vsini108 km/s
• Literature Results
• 8700 (410,-198) K

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HD 34282
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HD 34282 Balmer Fits
Best Fit 9800 K, Log(g)4.5
Best Fit 10100 K, Log(g)4.5
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HD 36112

• A8e Classification
• Best Fit
• 7900 K
• Log(g)4.0
• vsini52 km/s
• Literature Results
• 7700 K

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HD 36112
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HD 36112 Balmer Fits
Best Fit 8000 K, Log(g)5.0
Best Fit 8100 K, Log(g)5.0
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HD 31648

• A3pshe Classification
• Best Fit
• 8200 K
• Log(g)3.5
• vsini95 km/s
• Literature Results
• 8700 K
• 9250 K, Log(g)3.5

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HD 31648
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Difficult StarsBF Ori

• A5II-IIIe var
• Best Fit
• 7500
• Log(g)4.0
• vsini53 km/s
• Literature Results
• 6750

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BF Ori
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HR DIAGRAMNew Temperatures
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HR DiagramNew Temperatures and Distances
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HR DiagramNew Temperatures and Computed
Photometry
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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.

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THE END
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Balmer Line Normalization HD36112
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Balmer Line Normalization HD139614
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Balmer Line NormalizationComparison between
ESPaDOnS and FORS1
HD 36112
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Uncertainty vs SNRFor 15000 K synthetic model
with 40 km/s vsini.
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15000 K synthetic model with 40 km/s vsini
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Difficult starsHD 31293
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HD 31293