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Eruptive prominence and associated CME observed with SUMER, CDS and LASCO (SOHO)
Schmieder, B.; Brekke, P.; Kucera, T. +3 more
Observations of an eruptive prominence were obtained on 1 May 1996, with the SUMER and CDS instruments aboard SOHO during the preparatory phase of the Joint Observing Programme JOP12. A coronal mass ejection observed with LASCO is associated temporally and spatially with this prominence. The main objective of JOP12 is to study the dynamics of prom…
Three massive binaries and the Struve-Sahade effect
Stickland, D. J.
The High Chromospheres of the Late A Stars
Simon, Theodore; Landsman, Wayne B.
We report the detection of N V 1239 Å transition region emission in HST/Goddard High Resolution Spectrograph spectra of the A7 V stars, α Aql and α Cep. Our observations provide the first direct evidence of 1-3 × 105 K material in the atmospheres of normal A-type stars. For both stars, and for the mid A-type star τ3 Eri, we a…
Injection of large grains into orbits around comet nuclei.
Fulle, M.
Starting from the nucleus surface, the motion of dust boulders of diameters larger than the solar radiation pressure resonance size (Richter & Keller, 1995Icar..114..355R) is investigated by numerical integration of the motion equation for times larger than the comet orbital period. The motion equation takes into account the comet nucleus grav…
A test of Tully-Fisher distance estimates using Cepheids and SNIa
Shanks, T.
We make a direct test of Tully-Fisher distance estimates to 11 spiral galaxies with Hubble Space Telescope (HST) Cepheid distances, and to 12 spiral galaxies with Type Ia supernova (SNIa) distances. The HST Cepheid distances come from the work of Freedman, Sandage et al. and Tanvir et al. The SNIa distances come from Pierce, calibrated using the C…
Non-LTE Line-blanketed Model Atmospheres of Hot Stars. III. Hot Subdwarfs: The sdO Star BD +75°325
Hubeny, Ivan; Heap, Sara R.; Lanz, Thierry
We have made a detailed comparison of results of spectroscopic analysis using three differents types of model atmospheres: classical non-LTE H-He models; approximate non-LTE line-blanketed models (with only a subset of Fe and Ni lines: those originating from transitions between levels with measured energies); and non-LTE fully blanketed models. Th…
Distance to the Coma Cluster and a Value for HO Inferred from Globular Clusters in IC 4051
Ajhar, Edward A.; Grillmair, Carl J.; Groth, Edward J. +4 more
We report HST-WFPC2 observations of the giant E2 galaxy IC 4051 located 14' east of the center of the Coma Cluster. Eight full-orbit exposures were obtained with the F606W filter, and two with the F814W filter. Counts of globular clusters (GCs) in 0.2-mag wide bins were made within the PC1 (f/28) frame, where faint GCs can be distinguished from no…
The Dust-to-Gas Ratio in the Damped Lyα Clouds toward the Gravitationally Lensed QSO 0957+561
Cohen, Ross D.; Junkkarinen, Vesa T.; Lyons, R. W. +3 more
We present HST/FOS1 spectra of the two bright images (A and B) of the gravitationally lensed QSO 0957+561 in the wavelength range 2200-3300 Å. We find that the absorption system (zabs = 1.3911) near zem is a weak, damped Lyα system with strong Lyα absorption lines seen in both images. However, the H I column densities are dif…
The Giant 1991 June 1 Flare: Evidence for Gamma-Ray Production in the Corona and Accelerated Heavy Ion Abundance Enhancements from Gamma-Ray Spectroscopy
Ramaty, Reuven; Mandzhavidze, Natalie; Barat, Claude +1 more
We investigated the implications of the gamma-ray line emission observed with Granat/PHEBUS from the behind-the-limb flare on 1991 June 1. We showed that thin target interactions are required to account for the very high observed ratio of the nuclear line emission in the 1.1-1.8 MeV and 4.1-7.6 MeV energy bands, which are populated predominantly b…
Nitrogen V in the wind of the pre-main sequence Herbig AE star AB Aurigae
Bouret, J. -C.; Catala, C.; Simon, T.
Recent GHRS observations of the Herbig Ae star AB Aur demonstrate the presence of N V in the wind of this star. This result reveals temperatures much higher than those previously considered for the wind of AB Aur. We show that homogeneous spherically symmetric models are unable to reproduce the available observations, including the C IV resonance …