Astromineralogy of the 13 μm Feature in the Spectra of Oxygen-rich Asymptotic Giant Branch Stars. I. Corundum and Spinel

Details Astromineralogy of the 13 μm Feature in the Spectra of Oxygen-rich Asymptotic Giant Branch Stars. I. Corundum and Spinel Astromineralogy of the 13 μm Feature in the Spectra of Oxygen-rich Asymptotic Giant Branch Stars. I. Corundum and Spinel

Apr 2006

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006apj...640..971d&link_type=abstract

The Astrophysical Journal, Volume 640, Issue 2, pp. 971-981.

Astronomy and Astrophysics

Astronomy

18

Stars: Circumstellar Matter, Ism: Dust, Extinction, Infrared: Stars, Stars: Agb And Post-Agb, Stars: Mass Loss

Scientific paper

Asymptotic giant branch (AGB) stars have several interesting infrared spectral features. Approximately half the oxygen-rich AGB stars to be investigated spectroscopically exhibit a feature at ~13 μm. The carrier of this feature has not yet been unequivocally identified but has been attributed to various dust species, including corundum (α-Al2O 3), spinel (MgAl2O4), and silica (SiO 2). In order to constrain the carrier of the 13 μm feature, we have used the one-dimensional radiative transfer code DUSTY to model the effects of composition and optical depth on the shape and strength of the emerging 13 μm feature from corundum and spinel grains. We have modeled various corundum, spinel, corundum-silicate, and spinel-silicate mixtures in dust shells surrounding O-rich AGB stars. These models demonstrate that (1) if corundum is present in these circumstellar dust shells, even at very low relative abundances, a ~13 μm feature should be observed; (2) corundum's weak ~21 μm feature will not be observed, even if it is responsible for the ~13 μm feature; (3) even at low relative abundances, spinel exhibits a feature at 16.8 μm that is not found in observations; and (4) the grains must be spherical. Other grain shapes (spheroids, ellipsoids, and hollow spheres) shift the features to longer wavelengths for both spinel and corundum. Our models show that spinel is unlikely to be the carrier of the 13 μm feature. The case for corundum as the carrier is strengthened but not yet proven.

Affiliated with

Also associated with

No associations

Rating

Astromineralogy of the 13 μm Feature in the Spectra of Oxygen-rich Asymptotic Giant Branch Stars. I. Corundum and Spinel does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Astromineralogy of the 13 μm Feature in the Spectra of Oxygen-rich Asymptotic Giant Branch Stars. I. Corundum and Spinel, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Astromineralogy of the 13 μm Feature in the Spectra of Oxygen-rich Asymptotic Giant Branch Stars. I. Corundum and Spinel will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1158235