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Radiative Transfer in Stellar Atmospheres

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Radiative Transfer in Stellar Atmospheres Quantitative IR astronomy A collaboration of Don Figer (STScI) Paco Najarro (CSIC) Margaret Hanson (Cinncinatti) Joachim Puls (Munich) Rolf Kudritzki (UH) The Arches Cluster in the Galactic Centre in IR colors SEDs of massive stars in star forming regions Æ heavy extinction Spectral Analysis Æ IR spectroscopy O-star SED (intrinsic) IR-excess stellar wind AV = 30 mag IR Spectral types: Hanson, Kudritzki et al., 2005 ApJS, astro-ph 0506705 Dwarfs O3 to O6 H-band K-Band IR Spectral types: Hanson, Kudritzki et al., 2005 ApJS, astro-ph 0506705 Dwarfs O7 to B2 H-band K-Band IR Spectral types: Hanson, Kudritzki et al., 2005 ApJS, astro-ph 0506705 Supergiants O3 to O5 H-band K-Band IR Spectral types: Hanson, Kudritzki et al., 2005 ApJS, astro-ph 0506705 Supergiants O9 to B0 H-band K-Band IR Spectral types: Hanson, Kudritzki et al., 2005 ApJS, astro-ph 0506705 Supergiants B0 to B3 H-band K-Band IR Spectral types: Hanson, Kudritzki et al., 2005 ApJS, astro-ph 0506705 Luminosity effects Spectral type O7 H-band K-Band IR Spectral types: Hanson, Kudritzki et al., 2005 ApJS, astro-ph 0506705 Luminosity effects Spectral type O9 H-band K-Band IR Spectral types: Hanson, Kudritzki et al., 2005 ApJS, astro-ph 0506705 Luminosity effects Spectral type B2 H-band K-Band The youngest massive stars in UCHII regions Hanson, Puls, Repolust & Kudritzki, 2005 G29.96 –0.02 HII: 0.1 pc (4”) Wood & Churchwell (1989) central Star: O5-O6V (Watson & Hanson 1997) Extinction: Av = 25 Age: <100,000 yrs? Subaru spectra of G29.96-0.02* resolution 10,000 S/N =200 S/N =60 H and K-band ‘classification’ indicates early-O, but precise luminosity, information about the wind, etc. is not obtainable. First fit results of G29.96-0.02* spectra Teff = 41,000K (O4/O5) log g = 3.8 vsini = 80 km/s -6 -1 R* = 18, vinf = 2200 km/s Æ mass-loss rate few x 10 Moyr S/N ( ~ 60) may not be high enough for a rigorous analysis. Model atmosphere fit: IR as good as optical Æ same results Repolust, Puls, Hanson, Kudritzki, Mokiem , 2005 A&A, astro-ph 0501606 typical line fits for dwarfs P Cygni - B2 hypergiant and LBV: Model atmosphere fit - optical lines Najarro & Kudritzki, 1997 P Cygni - B2 hypergiant and LBV: Model atmosphere fit – IR (ISO) Najarro & Kudritzki, 1997 P Cygni B2 hypergiant and LBV: Model atmosphere fit from UV to IR Far UV Najarro, 2005 P Cygni B2 hypergiant and LBV: Model atmosphere fit from UV to IR UV Najarro, 2005 P Cygni B2 hypergiant and LBV: Model atmosphere fit from UV to IR near UV Najarro, 2005 P Cygni B2 hypergiant and LBV: Model atmosphere fit from UV to IR blue Najarro, 2005 P Cygni B2 hypergiant and LBV: Model atmosphere fit from UV to IR green, yellow Najarro, 2005 P Cygni B2 hypergiant and LBV: Model atmosphere fit from UV to IR near IR Najarro, 2005 P Cygni B2 hypergiant and LBV: Model atmosphere fit from UV to IR mid IR (ISO) Najarro, 2005 Black Hole Quantitative spectroscopy of the stellar population in the galactic center •AV ≥ 30 mag Æ IR is the only way to obtain information • energy, momentum and impact on star formation Æ ionizing radiation, stellar wind outflows • age of the stellar population •metallicity • star formation rate, IMF, feeding the black hole • kinematics of the stellar population, vrad and d/dt (vrad) Æ black hole mass IR integral field spectrosocopy with AO of GC stars within 1 pc, Krabbe et al. (1995) Æ Emission line stars and Wolf-Rayet stars (WC 9/Of) Typical example for GC emission line stars: the AF star Najarro, Hillier, Kudritzki et al., 1994 The nature of the HeI 2.06 µ emission Quantitative spectroscopy of emission line stars: AF star Ævery luminous evolved B-supergiants with strong stellarwinds Galactic Center Clusters The monster in the Quintuplet cluster Figer et al. 1999, ApJ, 525, 759 Two extremely massive stars Pistol Star Star #362 Figer et al. 1999, ApJ, 525, 759 Geballe et al. 2000, ApJ, 530, 97 Pistol Star in HRD tracks by Langer Figer et al. 1998, ApJ, 506, 384 model fit model fit model fit Galactic Center Clusters Arches stars:WN9 stars HeI NIII HeI HeI/HI HeII Figer et al. 2002, ApJ, enhanced Nitrogen NIII NIII 581, 258 Arches stars: O stars HI 68 HeI 27 Figer et al. 2002, ApJ, 581, 258 Arches stars: quantitative spectroscopy NIII NIII NIII Najarro, Figer, Hillier, Kudritzki, 2004, ApJ Letters Age and metallicity through nitrogen abundances Najarro, Figer, Hillier, Kudritzki, 2004, ApJ Letters The X-ray emission of hot, massive stars • all O- stars show X-ray emission -7 •LX/LBol ≈ 10 , but large scatter • hypothesis: hot shocks in stellar wind emit X-rays • X-rays affect stellar wind ionization Æ OVI, SVI, NV • wind models need to include X-rays • comprehensive study of X-ray emission (Kudritzki et al., 98) using ROSAT X-ray SEDS and radiative transfer model for randomly distributed shocks imbedded into winds time dependent stellar wind radiation-hydro Æ shocks (Owocki et al., 1988; Feldmeier, 1997, thesis) Röntgensatellit 01 June 1990 Cape Canaveral MPE ROSAT X-ray Telescope max aperture 83 cm focal length 240 cm collecting area 1140 cm2 on-axis resolution 3” energy band 0.1 – 2.4 keV 124 – 5 Å MPE ROSAT’s Mirrors 4 nested Wolter type I mirrors MPE Calculated spectra and ROSAT observations Feldmeier, Kudritzki et al., 1997 ζ Pup, O4 If ι Ori O9 III 15 Mon O7 V theory convolved with ROSAT FWHM ● ROSAT X-ray Luminosity of O-stars Kudritzki et al., 1998.
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