Browsing by Identifier "0004-637X"
Now showing items 1-8 of 8
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Anomalous Silicate Dust Emission in the Type 1 Liner Nucleus of M81
(American Astronomical Society, 2010)We report the detection and successful modeling of the unusual 9.7μm Si-O stretching silicate emission feature in the type 1 (i.e., face-on) LINER nucleus of M81. Using the Infrared Spectrograph (IRS) instrument on Spitzer, ... -
Astromineralogy of the 13 μm Feature in the Spectra of Oxygen-rich Asymptotic Giant Branch Stars. I. Corundum and Spinel
(American Astronomical Society, 2006)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 ... -
The Dust Ring of Luminous Blue Variable Candidate HD 168625: Infrared Observations and Model Calculations
(Institute of Physics, 2003)We present a 2.218 lm image from the Hubble Space Telescope/Near Infrared Camera and Multi-Object Spectrometer (NICMOS) and a 55 lm image from ISOPHOT of the dust ring surrounding the luminous blue variable (LBV) candidate ... -
The Effect of Stellar Evolution on SiC Dust Grain Sizes
(American Astronomical Society, 2005)Stars on the asymptotic giant branch (AGB) produce dust in their circumstellar shells. The nature of the dust-forming environment is influenced by the evolution of the stars, in terms of both chemistry and density, leading ... -
The Mass-loss Return from Evolved Stars to the Large Magellanic Cloud. II. Dust Properties for Oxygen-rich Asymptotic Giant Branch Stars
(American Astronomical Society, 2010)We model multi-wavelength broadband UBVIJHKs and Spitzer IRAC and MIPS photometry and Infrared Spectrograph spectra from the SAGE and SAGE-Spectroscopy observing programs of two oxygen-rich asymptotic giant branch (O-rich ... -
Optical Constants of Silicon Carbide for Astrophysical Applications. II. Extending Optical Functions from Infrared to Ultraviolet Using Single-Crystal Absorption Spectra
(American Astronomical Society, 2009)Laboratory measurements of unpolarized and polarized absorption spectra of various samples and crystal structures of silicon carbide (SiC) are presented from 1200-35000 cm−1 (λ ∼ 8-0.28 μm) and used to improve the accuracy ... -
Processing of Presolar Grains around Post-Asymptotic Giant Branch Stars: Silicon Carbide as the Carrier of the 21 Micron Feature
(Institute of Physics, 2004)Some proto-planetary nebulae (PPNs) exhibit an enigmatic feature in their infrared spectra at ~21 μm. This feature is not seen in the spectra of either the precursors to PPNs, the asymptotic giant branch (AGB) stars, or ... -
Progress in Measurements of the Gravitational Bending of Radio Waves Using the VLBA
(American Astronomical Society, 2009)We have used the Very Long Baseline Array (VLBA) at 43, 23, and 15 GHz to measure the solar gravitational deflection of radio waves among four radio sources during an 18 day period in 2005 October. Using phase- referenced ...