Search Publications
Atmospheric chemical composition of the "twin" components of equal mass in the CP SB2 system 66 Eri
Bikmaev, I. F.; Yushchenko, A. V.; Musaev, F. A. +2 more
We determine the atmospheric chemical composition of the components of the CP SB2 system 66 Eri with approximately equal masses (M_A / M_B = 0.97) by using two CCD echelle spectra of the star. These spectra have been taken with the 1-m telescope at Special Astrophysical Observatory with a spectral resolution of 36 000 and a signal-to-noise ratio n…
IRAS04496-6958: A luminous carbon star with silicate dust in the Large Magellanic Cloud
Waters, L. B. F. M.; Blommaert, J. A. D. L.; Whitelock, Patricia A. +7 more
We describe ISO observations of the obscured Asymptotic Giant Branch (AGB) star IRAS04496-6958 in the Large Magellanic Cloud (LMC). This star has been classified as a carbon star. Our new ISOCAM CVF spectra show that it is the first carbon star with silicate dust known outside of the Milky Way. The existence of this object, and the fact that it is…
Towards understanding rapid line-profile and light variations of early-type stars. 3. Some thoughts and reflections
Harmanec, P.
The current situation in the research of rapid line-profile and light variations of early-type stars is critically reviewed. It is suggested that the ultimate understanding of the physical processes causing these variations can only come from an open-minded and complex approach to the problem and from systematic observational effort. It is argued …
Ultraviolet Imaging Polarimetry of Narrow-Line Radio Galaxies
Antonucci, Robert; Hurt, Todd; Cohen, Ross +2 more
In an examination of the unification of radio galaxies and quasars, we obtained UV polarization images of eight narrow-line radio galaxies (NLRGs) with the Faint Object Camera on board the Hubble Space Telescope (HST). By observing in the rest ultraviolet, we can measure the polarization of the active nucleus with little contamination from unpolar…
GHRS and ORFEUS II Observations of the Highly Ionized Interstellar Medium toward ESO 141-055
Sembach, Kenneth R.; Savage, Blair D.; Hurwitz, Mark
We present Goddard High Resolution Spectrograph (GHRS) and ORFEUS II measurements of Si IV, C IV, N V, and O VI absorption in the interstellar medium of the Galactic disk and halo toward the nucleus of the Seyfert galaxy ESO 141-055. The high-ionization absorption is strong, with line strengths consistent with the spectral signature expected for h…
Analysis of Extreme-Ultraviolet Off-Limb Spectra Obtained with SUMER/SOHO: Ne VI-Mg VI Emission Lines
Wilhelm, Klaus; Dwivedi, Bhola N.; Curdt, Werner
We present results from a study of extreme-ultraviolet (EUV) off-limb spectra. These were obtained on 1996 June 20 with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument on the Solar and Heliospheric Observatory (SOHO). With the capabilities of SUMER, we rastered the emitting source from 40" off the limb outward, and secur…
Latitudinal properties of the Lyman alpha and O VI profiles in the extended solar corona
Romoli, M.; Poletto, G.; Noci, G. +3 more
We have analysed the latitudinal properties of the profiles of the H I Lyman alpha line at 1215.6 protect Angstroms and of the O VI doublet at 1031.9 protect Angstroms and 1037.6 protect Angstroms in the extended solar corona, between 1.5 R_sun and 2.0 R_sun. Observations have been performed with the UltraViolet Coronagraph Spectrometer (UVCS) on …
Very young massive stars in the Small Magellanic Cloud, revealed by HST
Heydari-Malayeri, M.; Charmandaris, V.; Zinnecker, H. +2 more
High spatial resolution imaging with the Hubble Space Telescope allowed us to resolve the compact H ii region N 81 lying in the Small Magellanic Cloud (SMC). We show the presence of a tight cluster of newborn massive stars embedded in this nebular ``blob'' of ~ 10'' across. This is the first time the stellar content and internal morphology of such…
Imprint of the Sun on the Solar Wind
Habbal, Shadia Rifai; Woo, Richard
Observations of the inner corona in polarized brightness by the Mauna Loa Mk III K-coronameter at 1.15 Rsolar and soft X-rays by Yohkoh at 1.03 Rsolar are combined with 1995 Ulysses radio occultation measurements of the solar wind to demonstrate that the signatures of the coronal hole boundary, active regions, and bright poin…
Infrared Space Observatory Photometric Search of Main-Sequence Stars for Vega-Type Systems
Stencel, R. E.; Backman, D. E.; Fajardo-Acosta, S. B. +1 more
We obtained 3.6-20 µm photometry of 38 bright [IRAS Fν(12 µm)>0.7 Jy] main-sequence stars with the Infrared Space Observatory (ISO). Observations were conducted with the ISOPHOT instrument, in the single-pointing photometry mode, through filters at 3.6, 11.5, and 20.0 µm. We searched for excess (Vega-type) emission …