Search Publications
Overview of recent analysis of the energetic particle observations recorded in Situ by the EPONA instrument on the Giotto Mission to Comet Halley
Neubauer, F. M.; Daly, P.; McKenna-Lawlor, S. M. P. +4 more
Highlights of recent results obtained through analyzing data recorded by the energetic particles experiment EPONA on the Giotto Mission to Comet Halley (March 12-15, 1986) from ∼7 × 10 6 km upstream of the bow shock (inbound) to ∼6 × 10 6 km upstream of the bow shock (outbound) are presented. The identities of the ions record…
The Ultraviolet Spectrum of the Be-Star 88-HERCULIS
Danezis, E.; Theodossiou, E.
In this paper, we give a detailed list and analysis of line identifications of the UV spectrum of the Be star 88 Her in the wavelength range λλ1958–3002 Å recorded in 1984, 23 May with the International Ultraviolet Explorer (IUE). The spectrum is crowded by shell absorptions lines, mostly those of singly ionized iron peak elements. The detailed an…
Search for chromospheric MgII emission in Ap-type stars.
Seggewiss, W.
Observations of the Mg II h and k line resonance doublet in the spectra of 10 of the latest Ap-type stars show no sign of emission cores in the broad absorption lines. Thus, the Mg II lines give no evidence for chromospheric activity in peculiar A-type stars; the present observations sharpen the boarder between active and non-active stars. This fa…
Multifrequency Behaviour of the Dwarf Nova Ss-Cygni
Rossi, C.; Gaudenzi, S.; Giovannelli, F. +3 more
Several years of coordinated multifrequency observations of the dwarf nova SS Cygni have been performed in order to study the accretion behaviour of this system in particular, and in general to clarify this crucial problem for the cataclysmic variables. From IUE measurements, together with those from optical and IR ground based telescopes, we have…
Optical positions of radiostars. II.
Costa, E.; Loyola, P.
Precise optical positions, relative to either the Perth 70 or the AGK3R catalogs, have been obtained for 40 radiostars proposed to the Hipparcos observing list. Precision levels between 0.18 and 0.29 arcsecs were obtained.
Ultraviolet Spectra of Field Horizontal Branch A-Type Stars. II.
Adelman, Saul J.; Philip, A. G. Davis; Hayes, D. S.
The spectra of six additional A-type stars have been obtained at low resolution between 1200 and 1900 A with the IUE. The energy distributions of four of the stars match that of the field horizontal branch (FHB) distribution in Huenemoerder et al. (1984) while those of the other two do not. Three of the FHB stars fall above a line in the C(19 - V)…
The ultraviolet spectrum of the hydrogen-poor binary HD 30353.
Hack, M.; Parthasarathy, M.; Tektunali, G.
An analysis is made of the high- and low-resolution UV spectra of the hydrogen-poor star HD 30353. The stellar wind profiles of the resonance lines of N V, C V, and Si IV are found to be similar to those observed in Upsilon Sgr. However, HD 30353 shows shortward-shifted profiles also in the ground-level lines of Fe II, in the subordinate multiplet…
Multifrequency Observations of the Optically Active Radio-quiet Quasar GQ Comae. I. Ultraviolet Continuum and Line Variability
Sitko, Michael L.
This paper summarizes the data and preliminary results of a 3 year project to monitor the continuum variability of GQ Com in the satellite ultraviolet and the associated variability of the Lyα and C IV lines. Simultaneous and nearly simultaneous ground-based optical and infrared data were also obtained, but these will be discussed more fully in a …
LTE analysis of the far-ultraviolet variations of 21 Comae.
Monier, R.; Megessier, C.
The far-ultraviolet variations of the cool Ap star 21 Com in the spectral region 1450 - 1510 A are studied by using synthetic spectra. The integrated flux of the star is calculated, and the effective temperature of the star is derived and found to be lower than previous estimates. The computation of synthetic spectra indicates that the flux at the…
Ultraviolet Gas Absorption and Dust Extinction toward M8
Bohm-Vitense, Erika; Boggs, Don
Interstellar absorption lines are analyzed using high-resolution IUE spectra of 11 stars in the young cluster NGC 6530 located in the M8 region. High-velocity clouds at -35 km/s and -60 km/s are seen toward all cluster stars. The components arise in gases that are part of large interstellar bubbles centered on the cluster and driven by stellar win…