Search Publications
Circumstellar Absorption and Emission in the Post-AGB Stars HR4049 and HD213985
Waters, L. B. F. M.; Van Winckel, H.; Waelkens, C. +1 more
The evolved C-rich low-mass stars HR 4049 and HD 213985 present variable circumstellar extinction and emission. Observations of HR 4049 strengthen the link between the far-UV extinction rise and the presence of small C-rich particles. Variability of the UV absorption bump in HD 213985 is reported here for the first time and is discussed.
New kinematic distances of NGC 7009 and BD+30°3639 from UV and radio data
Maciel, W. J.
Measurements of the equivalent width of the interstellar Lymanα line from IUE spectra in the direction of the planetary nebulae NGC 7009 and BD+30°3639 are used to infer the H column density in these directions. Hydrogen 21 cm profiles are also used in connection with the ultraviolet data so that the expected rotation velocities and distances can …
Astronomical Archives and Their Importance for Knowledge Transfer in Basic Space Science
Wamsteker, W.; Griffin, R. E. M.
We summarize the nature of modern astronomical archives with special reference to spectroscopic data archives and illustrate in which ways archives can play a role in the accelerated development of Basic Space Sciences in the developing countries. Some of the conflicting issues in the current planning of archives are addressed. Astronomical spectr…
A search for planetary system candidates: Northern Nearby A Stars With Dust Disks And Circumstellar Gas
Cheng, Kwang-Ping; Neff, James E.
We report on our search for possible planetary system candidates in a volume-limited sample of 62 nearby A stars. Since the evolutionary lifetimes of A stars (≤ 109 yrs) roughly correspond to the era of planet formation and subsequent "heavy bombardment" in our solar system, our study could provide valuable insight into the origin of ou…