Kinematical Structure of Wolf-Rayet Winds. II. Internal Velocity Scatter in WN Stars

• Autorzy: Niedzielski A. , Nugis T. , Skórzyński W.
• Języki publikacji: EN

Abstrakty

EN

The shortward edge of the absorption core velocities - v_black as determined from low resolution archived IUE spectra from the INES database are presented for three P Cyg profiles of NV 1240, HeII 1640 and NIV 1720 for 51 Galactic and 64 LMC Wolf-Rayet stars of the WN subtype. These data, together with v_black of CIV 1550 line presented in Niedzielski and Skórzyński (2002) are discussed. Evidences are presented that v_black of CIV 1550 rarely displays the largest wind velocity among the four lines studied in detail and therefore its application as an estimator of the terminal wind velocity in WN stars is questioned. An average v_black of several lines is suggested instead but it is pointed out that v_black of HeII 1640 usually reveals the highest observable wind velocity in Galactic and LMC WN stars. It is shown that the stratification strength decreases from WNL to WNE stars and that for WNL stars there exists a positive relation between v_black and the Ionization Potential. The velocity scatter between v_black obtained from different UV lines is found to correlate well with the X-ray luminosity of single WN stars (correlation coefficient R=0.82 for the data obtained from the high resolution IUE spectra) and therefore two clumpy wind models of single WN stars are presented that allow the velocity scatter to persist up to very large distances from the stellar surface (r≈500-1000R_*). These models are used to explain the specific features of single WN stars like broad absorption troughs of strong lines having different v_black, X-ray fluxes, IR/radio continua and stratification relations.

Słowa kluczowe

EN

stars: Wolf-Rayet; stars: atmospheres; stars: winds; stars: outflows

• Wydawca: Copernicus Foundation for Polish Astronomy
• Czasopismo: Acta Astronomica
• Rocznik: 2004
• Tom: Vol. 54, No. 4
• Strony: 405--427
• Opis fizyczny: Bibliogr. 61 poz., tab., wykr.

Twórcy

autor

Niedzielski A.

• Toruń Centre for Astronomy, N. Copernicus University, ul. Gagarina 11, 87-100 Toruń, Poland

autor

Nugis T.

• Tartu Observatory, 61602 Tõravere, Estonia

autor

Skórzyński W.

• Department of Theoretical Foundations of Biomedical Sciences and Medical Informatics, L. Rydgier Medical University, ul.Jagiellońska 13, 85-094 Bydgoszcz, Poland

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