Dust Formation in Hot Stellar Winds

Author(s):  
I. Cherchneff ◽  
A. G. G. M. Tiellens
Keyword(s):  
1987 ◽  
pp. 455-456
Author(s):  
P. M. Williams ◽  
K. A. van der Hucht ◽  
P. S. Thé
Keyword(s):  

1993 ◽  
Vol 137 ◽  
pp. 572-574 ◽  
Author(s):  
E.A. Dorfi ◽  
M.U. Feuchtinger ◽  
S. Höfner

The cool extended atmospheres of late type giants are sites where dust formation takes place. Radiation pressure on the dust grains is an important force for driving the slow but massive winds observed in such objects. Existing calculations of dust driven stellar winds (e.g. Bowen 1988, Fleischer et al. 1991) suffer from the fact that they include approximations at various levels for different parts of the problem like the hydrodynamics or the dust formation. Furthermore they do not include time-dependent radiative transfer.In order to overcome these insufficiencies we plan to calculate self-consistent models of dust driven winds with a full description of both the radiation hydrodynamics and the time-dependent dust formation. As a first step, however, we concentrate our investigations on the self-consistent description of the radiation hydrodynamics adopting only a simple description of the dust opacities.


1988 ◽  
Vol 103 ◽  
pp. 57-64
Author(s):  
Robert E. Stencel

AbstractThis review describes recent conclusions about the physical environment of red giant and supergiant stars. This includes coronae, chromospheres, dust formation and stellar winds. This knowledge can provide the boundary conditions for considering what role such objects play as members of binary star systems, where tidal forces and companion behavior alter observed characteristics.


1987 ◽  
Vol 122 ◽  
pp. 533-534
Author(s):  
H.-P. Gail

A mechanism is proposed for the initiation of dust formation in stellar winds of M-type giants and supergiants. If Mg and Fe are ionized (M0…M4) dust formation is initiated by homogeneous nucleation of SiO, otherwise (later ≍ M2) by homogeneous nucleation of MgS. The condensation temperatures for these mechanisms agree well with observations.


1991 ◽  
Vol 143 ◽  
pp. 417-420
Author(s):  
P.M. Williams ◽  
K.A. Van Der Hucht ◽  
P.S. Thé ◽  
P. Bouchet ◽  
G. Roberts

A number of Wolf-Rayet stars show variations of up to a factor of ten in their infrared emission on timescales of months to years while their photospheric luminosities remain unchanged. This can be interpreted in terms of variation in the rates at which dust grains form in their stellar winds. Our data show variable circumstellar dust emission from WR 70 (HD 137603), with an episode of enhanced dust formation in early 1989, and fading of emission by dust formed around WR 48a (in 1979) and WR 19 some time before our first observation in 1988. We consider their relation to WR 140 (HD 193793), which forms dust in its wind for a few months at intervals of 7.94 years.


1995 ◽  
Vol 163 ◽  
pp. 346-354
Author(s):  
I. Cherchneff ◽  
A.G.G.M. Tielens

WC-type Wolf-Rayet stars show episodic or persistent infrared emission attributed to amorphous carbon grains forming in their winds. The process of dust formation in the hydrogen-poor environments characteristic of WC winds is reviewed and compared to the chemical pathway to soot particle production in AGB stars. Emphasis is put on the formation of the dust precursors, and the physical conditions necessary to nucleate them in WC winds. In particular, it is concluded that dust formation around WC stars occurs in a dense, largely neutral, circumstellar disk.


Author(s):  
K. A. van der Hucht ◽  
P. M. Williams ◽  
P. S. Thé
Keyword(s):  

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