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UV and optical observations of nova Sagittarii 1982.
Mazeh, T.; Netzer, H.; Cacciari, C. +6 more
Ultraviolet and optical observations of Nova Sagittarii 1982, are presented and discussed. The light curve and continuum energy distribution give a distance estimate of 4.7 kpc, visual extinction of 1±0.3 mag and Mv(max) = -6.35±0.5 mag. Simultaneous ultraviolet and optical data obtained 4 d after visual maximum, enable to study in deta…
IUE observations of comet P/Crommelin (1983 n)
Keller, H. U.; Evans, A.; Wallis, M. K. +2 more
Comet P/Crommelin has always been a difficult object to observe because of both its intrinsic faintness and its poor location in northern skies at the time of maximum activity. Observations were attempted with the International Ultraviolet Explorer (IUE) over a seven week period starting five days after the comet had reached perihelion. The nature…
Ultraviolet observations of the central star in the planetary nebula 136+5 1.
Heckathorn, J. N.; Fesen, R. A.
Ultraviolet spectra obtained with IUE are presented which confirm the Heckathorn et al. (1982) stellar candidate as the central star of the recently discovered planetary nebula 136+5°1. Spectra of the star covering the 1200 - 2000 Å range show a featureless continuum indicative of a black body temperature between 50,000 and 60,000K. Anomalously lo…
Interstellar reddeningh law towards the nucleus of H Per.
Franco, M. L.; Stalio, R.; Magazzu, A.
The extinction curves in the direction of four early-B main-sequence stars located in the nucleus of h Per (BD + 56 deg 501, BD + 56 deg 510, BD + 56 deg 516 and BD + 56 deg 517) and compared to one another and to the extinction curves derived from eight stars located in the same general area but lying at different distances. Data from UBV photome…
Photometric and UV spectroscopic observations of 22 VUL at eclipse : observational evidence for an extended chromosphere of a solar type G supergiant.
Che-Bohnenstengel, A.; Schroeder, K. -P.
The solar spectral type supergiant (G3 Ib-II) of the 22 Vul binary has been observed photometrically and spectroscopically during its recent eclipse of the B9 V companion. From the new photometric observations the eclipse data given by Parsons and Ake (1984) can be slightly improved (period = 249.21 ± 0.2 days, mideclipse: JD 2446191.6 ± 0.2). The…
The ultraviolet absorption spectrum of NGC 4151.
Tarenghi, M.; Veron, P.; Veron-Cetty, M. P.
The analysis of all available low dispersion, short wavelength, large aperture IUE spectra of NGC 4151 taken prior to March 1982 shows a linear correlation between the depth of the absorption lines and the strength of the underlying emission; the absorption lines vanish while the continuum is still measurable. This is interpreted as being due to a…
Properties of dust in the Orion nebula.
Patriarchi, P.; Perinotto, M.
New observations of the Orion nebula very close to the Trapezium stars have been taken with the IUE satellite in order to improve knowledge of the dust properties in the nebula. The new data have been interpreted together with previous observations using multiscattering models with various distributions of the dust-to-gas ratio. The main result is…
An interpretation of the spectral variations of theta Coronae Borealis.
Underhill, A. B.
Measurements are presented of the strengths and displacements of sharp absorption components of the resonance lines of Si IV, C IV, and Al III in the spectrum of θ CrB. No evidence is found for mass loss at a detectable rate. A qualitative model of a Be star is developed. It is suggested that the spectral variations of θ CrB are the result of chan…
The outer layers of the beta Cephei stars BW VUL and sigma Sco.
Blomme, R.; Hensberge, H.
Mass loss rates for the Beta Cephei stars BW Vul and Sigma Sco have been derived from the C IV and Si IV resonance lines, which are formed in the outflowing layers. Assuming an ionization fraction log q(C IV) = -1.9, mass losses of 1.4 and 1.9 x 10 to the -9th solar mass/yr are predicted for BW Vul and Sigma Sco, respectively. In the case of BW Vu…
M 62 : an RR Lyrae-rich, UV-bright galactic globular cluster.
Tarenghi, M.; Caloi, V.; Castellani, V.
The central region of the globular cluster M62 was observed with IUE. The authors confirm that, in the UV, M62 is the brightest cluster observed up to now in the galaxy. This RR Lyrae-rich system is another example of an UV-bright cluster with a horizontal branch not confined to the blue. The interpretation of UV excesses from spiral nuclei and el…