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

Niedzielski A., Nugis T., Skórzyński W.

Acta Astronomica

2004

Vol. 54, No. 4

405--427

The shortward edge of the absorption core velocities - vblack 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 vblack of CIV 1550 line presented in Niedzielski and Skórzyński (2002) are discussed. Evidences are presented that vblack 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 vblack of several lines is suggested instead but it is pointed out that vblack 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 vblack and the Ionization Potential. The velocity scatter between vblack 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 vblack, X-ray fluxes, IR/radio continua and stratification relations.

First Results of the Semi-Automatic Variability Search

Niedzielski A., Maciejewski G., Czart K.

Acta Astronomica

2003

Vol. 56, No. 3

281--290

A short description of the Semi-Automatic Variability Search is given. Six new red variable stars discovered recently are presented: GSC 02907-00779, GSC 02904-00834, GSC 02908-00024, GSC 02976-00401, BD+42°1814 and HD 76190.

Tables of the Partition Functions for Iron, Fe I-Fe X

Halenka J., Madej J.

Acta Astronomica

2002

Vol. 52, No. 2

195--202

We present extensive tables of the Atomic Partition Function for iron ions, Fe I-Fe X, and discuss details of the computational method. Partition functions are given in wide range of temperatures, 10³ K6 K, and lowering of ionization energy (0.001 eV

Tables of the Partition Functions for Nickel, Ni I-Ni X

Halenka J., Madej J., Langer K., Mamok A.

Acta Astronomica

2001

Vol. 51, No. 4

347--352

We present extensive tables of the atomic partition functions (APFs) for nickel ions, Ni I-Ni X. Partition functions are given over wide range of temperature, 10³ K6 K, and lowering of ionization energy (0.001 eV