scholarly journals P Cygni profiles variability in central stars of Planetary Nebulae

1997 ◽  
Vol 180 ◽  
pp. 125-125
Author(s):  
P. Patriarchi ◽  
M. Perinotto
Keyword(s):  
Mass Loss ◽  
Planetary Nebulae ◽  
Associated Mass ◽  
Central Stars ◽  
Loss Rates

The variability of P Cygni profiles is important because of its connection with the mechanism of wind production and with the behaviour of the associated mass loss rates.

Mass-loss rates and C/He ratios in the winds of the WC central stars of planetary nebulae

1993 ◽  
Vol 260 (2) ◽  
pp. 401-407 ◽  
Author(s):  
J. A. de Freitas Pacheco ◽  
R. D. D. Costa ◽  
F. X. de Araujo ◽  
D. Petrini
Keyword(s):  
Mass Loss ◽  
Planetary Nebulae ◽  
Central Stars ◽  
Loss Rates

scholarly journals Stellar wind models of central stars of planetary nebulae

2020 ◽  
Vol 635 ◽  
pp. A173 ◽  
Author(s):  
J. Krtička ◽  
J. Kubát ◽  
I. Krtičková
Keyword(s):  
Mass Loss ◽  
White Dwarf ◽  
Planetary Nebula ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Planetary Nebulae ◽  
Terminal Velocity ◽  
Asymptotic Giant Branch ◽  
Central Stars ◽  
Loss Rates

Context. Fast line-driven stellar winds play an important role in the evolution of planetary nebulae, even though they are relatively weak. Aims. We provide global (unified) hot star wind models of central stars of planetary nebulae. The models predict wind structure including the mass-loss rates, terminal velocities, and emergent fluxes from basic stellar parameters. Methods. We applied our wind code for parameters corresponding to evolutionary stages between the asymptotic giant branch and white dwarf phases for a star with a final mass of 0.569 M⊙. We study the influence of metallicity and wind inhomogeneities (clumping) on the wind properties. Results. Line-driven winds appear very early after the star leaves the asymptotic giant branch (at the latest for Teff ≈ 10 kK) and fade away at the white dwarf cooling track (below Teff = 105 kK). Their mass-loss rate mostly scales with the stellar luminosity and, consequently, the mass-loss rate only varies slightly during the transition from the red to the blue part of the Hertzsprung–Russell diagram. There are the following two exceptions to the monotonic behavior: a bistability jump at around 20 kK, where the mass-loss rate decreases by a factor of a few (during evolution) due to a change in iron ionization, and an additional maximum at about Teff = 40−50 kK. On the other hand, the terminal velocity increases from about a few hundreds of km s−1 to a few thousands of km s−1 during the transition as a result of stellar radius decrease. The wind terminal velocity also significantly increases at the bistability jump. Derived wind parameters reasonably agree with observations. The effect of clumping is stronger at the hot side of the bistability jump than at the cool side. Conclusions. Derived fits to wind parameters can be used in evolutionary models and in studies of planetary nebula formation. A predicted bistability jump in mass-loss rates can cause the appearance of an additional shell of planetary nebula.

scholarly journals Mass loss from central stars of planetary nebulae

1981 ◽  
Vol 59 ◽  
pp. 45-50
Author(s):  
Mario Perinotto ◽  
Piero Benvenuti ◽  
Carla Cacciari
Keyword(s):  
Mass Loss ◽  
Planetary Nebula ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Planetary Nebulae ◽  
Central Star ◽  
High Resolution Spectrum ◽  
Preliminary Evaluation ◽  
Associated Mass ◽  
Central Stars

AbstractFrom a high resolution spectrum taken with IUE, the central star of the planetary nebula IC 2149 is found to exibit a wind with edge velocity of 1440 ± 100 km s-1. Our preliminary evaluation of the associated mass loss rate gives 10-8 M0 yr-1. Other planetary nebulae nuclei are studied with low resolution IUE spectra and indications are found of mass loss rates consistent with the above value.

scholarly journals A method for calculation of line profiles in expanding atmospheres: Application to winds from central stars of planetary nebulae

1987 ◽  
Vol 122 ◽  
pp. 431-432
Author(s):  
M. Cerruti-Sola ◽  
H.J.G.L.M. Lamers ◽  
M. Perinotto
Keyword(s):  
Mass Loss ◽  
Stellar Wind ◽  
Planetary Nebulae ◽  
Line Profiles ◽  
Expanding Atmospheres ◽  
Associated Mass ◽  
Central Stars ◽  
Uv Range

The structure of a stellar wind and its associated mass loss can be derived from the analysis of ñ Cygni-like line profiles. These do better occur in the UV range and have been extensively observed with the Copernicus (900–1450 A) and IUE Satellites (1150–3200 A).

scholarly journals Mass Loss Rates in Central Stars of Planetary Nebulae

1989 ◽  
Vol 131 ◽  
pp. 293-300 ◽  
Author(s):  
M. Perinotto
Keyword(s):  
Mass Loss ◽  
Planetary Nebulae ◽  
Central Star ◽  
Line Radiation ◽  
The Status ◽  
The Right ◽  
Central Stars ◽  
Loss Rates

Central stars of planetary nebulae (PNCS) frequently exhibit fast winds (cf. Cerruti-Sola and Perinotto, 1985; C.P. and Grewing, this volume). They may be important for the structure of the whole nebula as well as for the evolution of the central star. Their speed is typically two orders of magnitude higher than that of the classical optically visible nebula, which in turn expands a few times faster than the most external winds detected in few cases in the radio domain.I review here the status of art in the determination of the mass loss rates (M) associated with these fast winds. I restrict myself to the ‘observational’ determinations. Only at the end I will say something about the predictions of multi-scattering line radiation wind driven theory in connection with one best studied object: N6C 6543. This allows one to conclude that this theory may be the right explanation also for these winds.

scholarly journals Observed Mass Loss from Central Stars of Planetary Nebulae

1993 ◽  
Vol 155 ◽  
pp. 57-64 ◽  
Author(s):  
M. Perinotto
Keyword(s):  
Mass Loss ◽  
Planetary Nebula ◽  
Planetary Nebulae ◽  
The Status ◽  
History Of ◽  
Central Stars ◽  
Loss Rates

In the Introduction we recall the mass loss history of a progenitor of a planetary nebula (PN). Then we concentrate on the status of knowledge of fast winds in central stars of planetary nebulae (CSPN) : the detection and statistics, the observed edge velocities, relationships of the edge velocities with other stellar or nebular parameters. We then summarize the methods used to derive the mass loss rates associated to the fast winds, and review the determinations of the “observed” mass loss rates. The comparison with predictions from the radiation driven theory (RDT) is then discussed as well as possible lines for future improvements.

scholarly journals Quantitative Investigations on Mass Outflow from Planetary Nebulae Nuclei

1989 ◽  
Vol 131 ◽  
pp. 318-318
Author(s):  
S. Cerrato ◽  
L. Bianchi ◽  
M. Grewing ◽  
M. Bässgen ◽  
G. Bässgen
Keyword(s):  
Mass Loss ◽  
Planetary Nebulae ◽  
Uv Spectra ◽  
Line Profiles ◽  
Mass Outflow ◽  
Central Stars ◽  
Loss Rates

Observed P-Cygni line profiles in the UV spectra of central stars of Planetary Nebulae (PNN) obtained with the IUE satellite has been fitted by theoretical profiles in order to determine mass loss rates.

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