Query : 2008A&A...486..229Z

2008A&A...486..229Z - Astronomy and Astrophysics, volume 486, 229-237 (2008/7-4)

Condensation of MgS in outflows from carbon stars.


Abstract (from CDS):

The basic mechanism responsible for the widespread condensation of MgS in the outflows from carbon-rich stars on the tip of the AGB is discussed with the aim of developing a condensation model that can be applied in model calculations of dust formation in stellar winds. The different possibilities for how MgS may be formed in the chemical environment of outflows from carbon stars are explored by some thermochemical calculations and by a detailed analysis of the growth kinetics of grains in stellar winds. The optical properties of core-mantle grains with an MgS mantle are calculated to demonstrate that such grains reproduce the structure of the observed 30µm feature. These considerations are complemented by model calculations of circumstellar dust shells around carbon stars. It is argued that MgS is formed via precipitation on silicon carbide grains. This formation mechanism explains some of the basic observed features of MgS condensation in dust shells around carbon stars. A weak secondary peak at about 33 ... 36µm is shown to exist in certain cases if MgS forms a coating on SiC. This new feature seems to have occasionally been observed.

Abstract Copyright:

Journal keyword(s): circumstellar matter - stars: mass-loss - stars: winds, outflows - stars: AGB and post-AGB

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 11178 1
2 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 7084 0
3 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 17478 0
4 IRC +10216 C* 09 47 57.40632 +13 16 43.5648           C9,5e 2344 0

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