Determination of mass-loss rates from the first order momentW 1 of unsaturated P Cygni line profiles

1982 ◽  
Vol 88 (1) ◽  
pp. 31-54 ◽  
Author(s):  
J. Surdej
Keyword(s):  
Mass Loss ◽  
Line Profiles ◽  
First Order ◽  
Loss Rates

scholarly journals Revisited Mass-Loss Rates of Planetary Nebula Nuclei Observed with IUE

1989 ◽  
Vol 131 ◽  
pp. 317-317
Author(s):  
D. Hutsemékers ◽  
J. Surdej
Keyword(s):  
Mass Loss ◽  
Planetary Nebula ◽  
Order Moment ◽  
Line Profiles ◽  
Improved Method ◽  
Low Resolution ◽  
First Order ◽  
Average Value ◽  
Resonance Doublet ◽  
Loss Rates

The first order moment of P Cygni line profiles has been computed for the case of resonance doublet and subordinate line transitions, using realistic velocity and opacity distributions. This improved method has allowed us to rederive mass-loss rates for a sample of 17 PNN observed in the low resolution mode with IUE. The average value of our mass-loss rates amounts to 10−7 M⊙/yr.

scholarly journals Measuring mass-loss rates and constraining shock physics using X-ray line profiles of O stars from the Chandra archive

2014 ◽  
Vol 439 (1) ◽  
pp. 908-923 ◽  
Author(s):  
David H. Cohen ◽  
Emma E. Wollman ◽  
Maurice A. Leutenegger ◽  
Jon O. Sundqvist ◽  
Alex W. Fullerton ◽  
...  
Keyword(s):  
Mass Loss ◽  
Line Profiles ◽  
Shock Physics ◽  
X Ray ◽  
Loss Rates

scholarly journals Stellar Winds and Mass-Loss Rates from Be Stars

1982 ◽  
Vol 98 ◽  
pp. 377-385 ◽  
Author(s):  
Theodore P. Snow
Keyword(s):  
Mass Loss ◽  
Stellar Evolution ◽  
Stellar Winds ◽  
Be Stars ◽  
Line Profiles ◽  
Sample Group ◽  
Show Evidence ◽  
Acceleration Zone ◽  
Low Levels ◽  
Loss Rates

Resonance-line profiles of SiIII and SiIV lines in 22 B and Be stars have been analyzed in the derivation of mass-loss rates. Of the 19 known Be or shell stars in the sample group, all but one show evidence of winds. It is argued that for stars of spectral type B1.5 and later, SiIII and SiIV are the dominant stages of ionization, and this conclusion, together with theoretical fits to the line profiles, leads to mass-loss rates between 10-11 and 3 × 10-9 for the stars. The rate of mass loss does not correlate simply with stellar parameters, and probably is variable with time. The narrow FeIII shell lines often seen in the ultraviolet spectra of Be stars may arise at low levels in the wind, below the strong acceleration zone. The mass-loss rates from Be stars are apparently insufficient to affect stellar evolution.

scholarly journals The Ionization in the Winds of O Stars and the Determination of Mass‐Loss Rates from Ultraviolet Lines

1999 ◽  
Vol 516 (2) ◽  
pp. 872-886 ◽  
Author(s):  
Henny J. G. L. M. Lamers ◽  
Stephan Haser ◽  
Alex de Koter ◽  
Claus Leitherer
Keyword(s):  
Mass Loss ◽  
Loss Rates

scholarly journals The Influence of the Ratio of Total to Selective Extinction on the Determination of the Mass Loss Rate of Wolf Rayet Stars from Infrared Excess Measurements

1982 ◽  
Vol 99 ◽  
pp. 197-201
Author(s):  
P.S. The ◽  
K.A. van der Hucht ◽  
M. Arens
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Near Infrared ◽  
Mass Loss Rate ◽  
Infrared Excess ◽  
Photometric Observations ◽  
Order Of Magnitude ◽  
Selective Extinction ◽  
Loss Rates

It is shown that the mass loss rate of the WN7 star HD 93162 decreases with larger values of the ratio of total to selective extinction R. for HD 93162 the mass loss rate will change one order of magnitude, only if ΔR ∼ 2. Mass loss rates are derived for nine other WR stars of which visual, red and near-infrared photometric observations were obtained.

scholarly journals Wind properties of variable B supergiants

2018 ◽  
Vol 614 ◽  
pp. A91 ◽  
Author(s):  
M. Haucke ◽  
L. S. Cidale ◽  
R. O. J. Venero ◽  
M. Curé ◽  
M. Kraus ◽  
...  
Keyword(s):  
Mass Loss ◽  
Mass Loss Rate ◽  
Empirical Relationship ◽  
Variable Stars ◽  
Stellar Winds ◽  
Radial Pulsation ◽  
Line Profiles ◽  
Stellar Radius ◽  
Wind Variability ◽  
Loss Rates

Context. Variable B supergiants (BSGs) constitute a heterogeneous group of stars with complex photometric and spectroscopic behaviours. They exhibit mass-loss variations and experience different types of oscillation modes, and there is growing evidence that variable stellar winds and photospheric pulsations are closely related. Aims. To discuss the wind properties and variability of evolved B-type stars, we derive new stellar and wind parameters for a sample of 19 Galactic BSGs by fitting theoretical line profiles of H, He, and Si to the observed ones and compare them with previous determinations. Methods. The synthetic line profiles are computed with the non-local thermodynamic equilibrium (NLTE) atmosphere code FASTWIND, with a β-law for hydrodynamics. Results. The mass-loss rate of three stars has been obtained for the first time. The global properties of stellar winds of mid/late B supergiants are well represented by a β-law with β > 2. All stars follow the known empirical wind momentum–luminosity relationships, and the late BSGs show the trend of the mid BSGs. HD 75149 and HD 99953 display significant changes in the shape and intensity of the Hα line (from a pure absorption to a P Cygni profile, and vice versa). These stars have mass-loss variations of almost a factor of 2.8. A comparison among mass-loss rates from the literature reveals discrepancies of a factor of 1 to 7. This large variation is a consequence of the uncertainties in the determination of the stellar radius. Therefore, for a reliable comparison of these values we used the invariant parameter Qr. Based on this parameter, we find an empirical relationship that associates the amplitude of mass-loss variations with photometric/spectroscopic variability on timescales of tens of days. We find that stars located on the cool side of the bi-stability jump show a decrease in the ratio V∞∕Vesc, while their corresponding mass-loss rates are similar to or lower than the values found for stars on the hot side. Particularly, for those variable stars a decrease in V∞∕Vesc is accompanied by a decrease in Ṁ. Conclusions. Our results also suggest that radial pulsation modes with periods longer than 6 days might be responsible for the wind variability in the mid/late-type. These radial modes might be identified with strange modes, which are known to facilitate (enhanced) mass loss. On the other hand, we propose that the wind behaviour of stars on the cool side of the bi-stability jump could fit with predictions of the δ−slow hydrodynamics solution for radiation-driven winds with highly variable ionization.

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