Dust formation and wind acceleration around the aluminum oxide–rich AGB star W Hydrae
Aki Takigawa1,*, Takafumi Kamizuka2, Shogo Tachibana3,† and Issei Yamamura4,5
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Science Advances 01 Nov 2017:
Vol. 3, no. 11, eaao2149
DOI: 10.1126/sciadv.aao2149
Abstract
Dust grains, formed around asymptotic giant branch (AGB) stars, are accelerated by stellar radiation to drive stellar winds, which supply freshly synthesized nuclides to the Galaxy. Silicate is the dominant dust species in space, but ~40% of oxygen-rich AGB stars are thought to have comparable amounts of aluminum oxide dust. Dust formation and the wind-driving mechanism around these oxygen-rich stars, however, are poorly understood. We report on the spatial distributions of AlO and 29SiO molecules around an aluminum oxide–rich M-type AGB star, W Hydrae, based on observations obtained with the Atacama Large Millimeter/submillimeter Array. AlO molecules were only observed within three stellar radii (Rstar), whereas 29SiO was distributed in the accelerated wind beyond 5 Rstar without significant depletion. This strongly suggests that condensed aluminum oxide dust plays a key role in accelerating the stellar wind and in preventing the efficient formation of silicate dust around W Hydrae.
( Wenn ich das richtig verstanden habe, dürfte ich hier den ganzen Artikel anzeigen, aber weil´s eh nur wenige interessiert, verbleibt es bei dem Abstract- den Rest bitte via link!)
