Results 1 to 10 of about 236 (117)
Crystalline silicates in AGB and post-AGB stars [PDF]
Symposium - International Astronomical Union, 1999 We discuss ISO spectroscopy of oxygen-rich dust shells surrounding evolved stars. The dust that condenses in the outflows of stars on the Asymptotic Giant Branch consists mainly of amorphous silicates and simple oxides. For high mass loss rates, crystalline silicates begin to appear at modest abundance. These crystalline silicates are cold and Fe-poor.
Waters, L.B.F.M., Molster, F.J.
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Mid-IR Spectra of AGB and Post-AGB Stars [PDF]
Symposium - International Astronomical Union, 1993 We have generated models of complete nova energy distributions, including the effects of the nova dust shell emission and absorption. In order to account for the dust, we require optical constants throughout the UV and EUV. Draine & Lee (1984) is the only source of such data for silicates.
C. J. Skinner +3 more
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Photometric and Polarimetric Observations of AGB and Post AGB Stars [PDF]
Symposium - International Astronomical Union, 2003 Photometric and polarimetric observations of Long-Period Variables (LPVs), carried out at Byurakan Observatory over the last few years, have yielded some interesting results. In particular, one of the important results obtained for Mira type variables is that there is a certain correlation between brightness and polarization: the maximum degree of ...
N. D. Melikian +3 more
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INFRARED TWO-COLOR DIAGRAMS FOR AGB STARS, POST-AGB STARS, AND PLANETARY NEBULAE [PDF]
The Astrophysical Journal, 2015 14 pages, 5 figures.
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Infrared spectroscopic study of a selection of AGB and post-AGB stars [PDF]
Monthly Notices of the Royal Astronomical Society, 2008 We present here near-infrared spectroscopy in the H and K bands of a selection of nearly 80 stars that belong to various AGB types, namely S type, M type and SR type. This sample also includes 16 Post-AGB (PAGB) stars. From these spectra, we seek correlations between the equivalent widths of some important spectral signatures and the infrared colors ...
Raman, V. Venkata, Anandarao, B. G.
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Magnetic fields of AGB and post-AGB stars [PDF]
Proceedings of the International Astronomical Union, 2018 AbstractThere is ample evidence for the presence of strong magnetic fields in the envelopes of (post-)Asymptotic Giant Branch (AGB) stars as well as supergiant stars. The origin and role of these fields are still unclear. This paper updates the current status of magnetic field observations around AGB and post-AGB stars, and describes their possible ...
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Post-AGB stars in the LMC and SMC [PDF]
Proceedings of the International Astronomical Union, 2011 AbstractGalactic post-AGB stars show a large diversity in chemical compositions as well as in the kinematical and geometrical properties of their circumstellar material. The theoretical interpretation is hampered by the lack of good distances to almost all Galactic objects.
Hans Van Winckel +7 more
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Light and Velocity Variability of Post-AGB Stars [PDF]
Symposium - International Astronomical Union, 2000 We have monitored velocity variability in nine proto-planetary nebulae (PPN) over a 5 year interval and have monitored light variability in 40 PPN over a 2 year interval. We find all nine of the objects to vary in velocity and almost all of the 40 to vary in light.
Bruce J. Hrivnak, Wenxian Lu
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AGB and post-AGB stars at high angular resolution [PDF]
Symposium - International Astronomical Union, 1999 High angular resolution observations have provided some valuable information on the circumstellar environment of AGB and post-AGB stars.We review the recent results obtained in this field and focus on observations showing evidence of non-sphericity at different spatial scales (envelope, jets, binarity, maser clumps, stellar “photosphere”, hot spots ...
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An infrared photometric and spectroscopic study of post-AGB stars [PDF]
Monthly Notices of the Royal Astronomical Society, 2017 We present here $Spitzer$ mid-infrared (IR) spectra and modeling of the spectral energy distribution (SED) of a selection of post-Asymptotic Giant Branch (PAGB) stars. The mid-IR spectra of majority of these sources showed spectral features such as polycyclic aromatic hydrocarbons (PAHs) and silicates in emission.
Raman, V. Venkata +3 more
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