ar X iv : a st ro - p h / 05 12 37 1 v 1 1 4 D ec 2 00 5 POLYCYCLIC AROMATIC HYDROCARBONS ORBITING HD 233517 , AN EVOLVED OXYGEN - RICH RED GIANT

Polycyclic Aromatic Hydrocarbons Orbiting Hd 233517, an Evolved Oxygen-rich Red Giant

We report spectra obtained with the Spitzer Space Telescope in the λ = 5 – 35 μm range of HD 233517, an evolved K2 III giant with circumstellar dust. For λ > 13 μm, the flux is a smooth continuum that varies approximately as ν. For λ < 13 μm, although the star is oxygen-rich, PAH features produced by carbon-rich species at 6.3 μm, 8.2 μm, 11.3 μm and 12.7 μm are detected along with likely broad...

ar X iv : a st ro - p h / 06 12 37 8 v 1 1 4 D ec 2 00 6 Magnetic fields , strings and cosmology

ar X iv : a st ro - p h / 04 02 03 7 v 1 2 F eb 2 00 4 PAHs and crystalline silicates in the bipolar post - AGB star IRAS 16279 − 4757 12

IRAS 16279−4757 belongs to a group of post-AGB stars showing both PAH bands and crystalline silicates. We present mid-infrared images, that resolve the object for the first time. The morphology is similar to that of the 'Red Rectangle' (HD 44179), the prototype object with PAHs and crystalline sili-cates. A two-component model and images suggest a dense oxygen-rich torus, an inner, low-density ...

ar X iv : a st ro - p h / 99 12 49 6 v 1 2 3 D ec 1 99 9 Atomic Carbon in the Envelopes of Carbon - Rich Post - AGB Stars

Received ; accepted – 2 – ABSTRACT Atomic carbon has been detected in the envelopes of three carbon-rich evolved stars: HD 44179 (=AFGL 915, the 'Red Rectangle'); HD 56126; and, tentatively, the carbon star V Hya. This brings to seven the number of evolved star envelopes in which CI has been detected. Upper limits were found for several other stars, including R CrB. CI was not detected in sever...

ar X iv : a st ro - p h / 05 12 61 7 v 1 2 7 D ec 2 00 5 3 D Spectroscopy of Herbig - Haro objects