A temporal study of oxygen-rich pulsating variable AGB star, T Cep: Investigation on dust formation and dust properties

Abstract

Pulsation is believed to be the leading cause of dusty mass loss from Asymptotic Giant Branch (AGB) stars. We present a temporal study of T Cep, a long-period Mira variable, using seven ISO SWS spectra, covering a 16-month period over a single pulsation cycle. The observed spectral dust features change over the pulsation cycle of this Mira. In general, the overall apparent changes in spectral features can be attributed to changes in the dust temperature, resulting from the intrinsic pulsation cycle of the central star. However, not all feature changes are so easily explained. Based on direct comparison with laboratory spectra of several potential minerals, the dust is best explained by crystalline iron-rich silicates. These findings contradict the currently favored dust formation hypotheses.

This article has been accepted for publication in The Astrophysical Journal. It is tentatively scheduled for the May 10, 2011, v732 -2 issue

References in corpus (8)

• Too little radiation pressure on dust in the winds of oxygen-rich AGB stars
• 2D Models for Dust-driven AGB Star Winds
• The Relationship between the Optical Depth of the 9.7 micron Silicate Absorption Feature and Infrared Differential Extinction in Dense Clouds
• Winds of M- and S-type AGB stars: an unorthodox suggestion for the driving mechanism
• Tracing the development of dust around evolved stars: The case of 47 Tuc
• Optical properties of silicon carbide for astrophysical applications I. New laboratory infrared reflectance spectra and optical constants
• Fundamental parameters, integrated RGB mass loss and dust production in the Galactic globular cluster 47 Tucanae
• The mass-loss return from evolved stars to the Large Magellanic Cloud III. Dust properties for carbon-rich asymptotic giant branch stars

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