Mechanics of deposition of sand (and dust formation in sand storms)

Optical/infrared observations of RV Tauri stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900157262 ◽

1987 ◽

Vol 122 ◽

pp. 537-540

Author(s):

M. J. Goldsmith ◽

A. Evans ◽

J. S. Albinson ◽

M. F. Bode

Keyword(s):

Dust Formation ◽

Infrared Excess ◽

Infrared Observations ◽

Dust Shells ◽

Discernible Difference

Optical/infrared observations of RV Tauri stars obtained at SAAO have allowed the natures of the dust shells around stars with infrared excess to be investigated. The data suggest that dust formation occurs sporadically and that some stars have multiple shells. There is no photometrically discernible difference between carbon- and oxygen-rich stars or their dust shells. There is some evidence that stars with higher metallicity have more dust.

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Zooming into the complex dusty envelopes of C-rich AGB stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318006300 ◽

2018 ◽

Vol 14 (S343) ◽

pp. 456-457

Author(s):

Foteini Lykou ◽

Josef Hron ◽

Daniela Klotz

Keyword(s):

Temperature Distribution ◽

Near Infrared ◽

Angular Resolution ◽

High Angular Resolution ◽

Dust Formation ◽

Agb Stars ◽

Circumstellar Envelopes ◽

Recent Advances ◽

Multi Wavelength

AbstractRecent advances in high-angular resolution instruments (VLT and VLTI, ALMA) have enabled us to delve deep into the circumstellar envelopes of AGB stars from the optical to the sub-mm wavelengths, thus allowing us to study in detail the gas and dust formation zones (e.g., their geometry, chemistry and kinematics). This work focuses on four (4) C-rich AGB stars observed with a high-angular resolution technique in the near-infrared: a multi-wavelength tomographic study of the dusty layers of the circumstellar envelopes of these C-rich stars, i.e. the variations in the morphology and temperature distribution.

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Dust formation in the winds of AGBs: the contribution at low metallicities

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stt732 ◽

2013 ◽

Vol 433 (1) ◽

pp. 313-323 ◽

Cited By ~ 38

Author(s):

M. Di Criscienzo ◽

F. Dell’Agli ◽

P. Ventura ◽

R. Schneider ◽

R. Valiante ◽

...

Keyword(s):

Dust Formation

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Dust Formation During Steel Production And Fe–C Melt Evaporation

Metallurgist ◽

10.1007/s11015-016-0250-6 ◽

2016 ◽

Vol 60 (1-2) ◽

pp. 47-53

Author(s):

A. G. Svyazhin ◽

D. A. Romanovich ◽

P. Krishna Rao

Keyword(s):

Steel Production ◽

Dust Formation

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On the onset of dust formation in AGB stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318006014 ◽

2018 ◽

Vol 14 (S343) ◽

pp. 119-128

Author(s):

David Gobrecht ◽

Stefan T. Bromley ◽

John M. C. Plane ◽

Leen Decin ◽

Sergio Cristallo

Keyword(s):

Emission Feature ◽

Stellar Atmospheres ◽

Nucleation Theory ◽

Classical Nucleation Theory ◽

Quantum Mechanical ◽

Dust Formation ◽

Agb Stars ◽

Promising Candidate ◽

Bending Modes ◽

Structure Calculations

AbstractA promising candidate to initiate dust formation in oxygen-rich AGB stars is alumina (Al2O3) showing an emission feature around ∼13μm attributed to Al−O stretching and bending modes (Posch+99,Sloan+03). The counterpart to alumina in carbon-rich AGB atmospheres is the highly refractory silicon carbide (SiC) showing a characteristic feature around 11.3μm (Treffers74). Alumina and SiC grains are thought to represent the first condensates to emerge in AGB stellar atmospheres. We follow a bottom-up approach, starting with the smallest stoichiometric clusters (i.e. Al4O6, Si2C2), successively building up larger-sized clusters. We present new results of quantum-mechanical structure calculations of (Al2O3)n, n = 1−10 and (SiC)n clusters with n = 1−16, including potential energies, rotational constants, and structure-specific vibrational spectra. We demonstrate the energetic viability of homogeneous nucleation scenarios where monomers (Al2O3 and SiC) or dimers (Al4O6 and Si2C2) are successively added. We find significant differences between our quantum theory based results and nanoparticle properties derived from (classical) nucleation theory.

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