P Cygni Research Articles

THE H{alpha} VARIATIONS OF {eta} CARINAE DURING THE 2009.0 SPECTROSCOPIC EVENT

We report on H{alpha} spectroscopy of the 2009.0 spectroscopic event of {eta} Carinae collected via SMARTS observations using the Cerro Tololo Interamerican Observatory 1.5 m telescope and echelle spectrograph. Our observations were made almost every night over a two-month interval around the predicted minimum of {eta} Car. We observed a significant fading of the line emission that reached a minimum 7 days after the X-ray minimum. About 17 days prior to the H{alpha} flux minimum, the H{alpha} profile exhibited the emergence of a broad, P Cygni type, absorption component (near a Doppler shift of -500 km s{sup -1}) and a narrow absorption component (near -144 km s{sup -1} and probably associated with intervening gas from the Little Homunculus Nebula). All these features were observed during the last event in 2003.5 and are probably related to the close periastron passage of the companion. We argue that these variations are consistent with qualitative expectations about changes in the primary star's stellar wind that result from the wind-wind collision with a massive binary companion and from atmospheric eclipses of the companion.

The extreme P-Cygni star HDE 316285

New line-blanketed models for the P-Cygni star HDE 316285 have been calculated. Representative model atoms for H, He I, He II, Ca I, Ca II, Mg I, Mg II, Al II, Al III, Fe II, and Fe III are included in the calculations. We confirm the basic parameters derived by Hillier et al. (1998) in an earlier unblanketed study, and also confirm that many of the optical metal lines are produced by continuum fluorescence. The charge exchange reaction Fe2+ + H ⇌ Fe+ + H + modifies the Fe ionization structure and significantly enhances the strength of the optical Fe II emission lines.

Line-blanketing in massive stars: new results

Until recently, a major deficiency of most spectroscopic modeling of hot stars was the neglect of line-blanketing. With the availability of new atomic data, faster computers, suitable approximations, and improved numerical techniques it is now feasible to include non-LTE line-blanketing due to CNO and iron group elements in atmospheric calculations. We highlight the capabilities of the present generation of models. New blanketing results are presented for WN and WC Wolf-Rayet stars, and for LBVs. Line-blanketing alters individual line strengths in unpredictable ways, and can significantly influence the determination of stellar parameters. We specifically highlight the UV spectral region in which the effects of Fe blanketing are directly manifested. The importance of the charge exchange reaction Fe2+ + H ⇌ Fe+ + H+ for modeling of the Fe emission lines in the extreme P-Cygni star HDE 316285 is illustrated.

Narrow absorption components and variability in ultraviolet P Cygni profiles of early-type stars

Etude des spectres UV de 21 etoiles de la sequence principale, geantes et supergeantes, de type B1-O4

A radiative ionization and thermal equilibrium model for the wind from P Cygni

Discussion de l'equilibre thermique du vent de P Cygni en fonction du rayon. Calcul des taux de perte de masse et des lois de vitesse

THE PROFILE OF HE I X5876 IN THE P-CYGNI-TYPE OF STAR HD 152408

ABSTRACT The blue-shifted absorption component of the P-Cygni profile at He I A5876 in HD 152408 (08: ) has been found to be extremely broad, extending -1000 km sec-1 from the emission maximum. This unusual profile is probably due to overpopulation of the lower level of 5876, which permits it to form throughout a greater extent of the expanding atmosphere than most other lines. This observation confirms Hutchings' identification of very large velocities in the blue-violet spectrum of HD 152408, and in particular his interpretation of a similar feature at He I 3889, which is metastable. The A5876 profile in HD 152408 is compared to those in the similar but less extreme PCygni star HD 151804 (08 laf), and in the Wolf-Rayet star HD 151932 (WN7-A). The similarity between the absorption components in HD 152408 and the WN star is striking. Key words: Of stars - expanding atmospheres

UBV OBSERVATIONS OF P CYGNI

UBV OBSERVATIONS OF P CYGNI

THE INFRARED SPECTRUM OF P CYGNI

THE INFRARED SPECTRUM OF P CYGNI

The Behaviour of Carbon, Nitrogen and Silicon in the Spectrum of P Cygni

The Behaviour of Carbon, Nitrogen and Silicon in the Spectrum of P Cygni

The Spectrum of P Cygni

The Spectrum of P Cygni

The spectrum of P Cygni between 4340A and 4650A

The spectrum of P Cygni between 4340A and 4650A

NOTE ON THE SPECTRUM OF P CYGNI

NOTE ON THE SPECTRUM OF P CYGNI

Preliminary note on the spectrum of P Cygni

Preliminary note on the spectrum of P Cygni