Search Publications
Non-thermal phenomena in the atmosphere of hot subdwarfs : X-ray upper limit for BD -3 2179.
Viotti, R.; Rossi, L.; Dantona, F.
The investigation of the nonthermal phenomena in the atmosphere of hot sublimunous stars (sdO) provides information for the study of the subatmospheric structure in evolved stars. It is noted that large mass outflows have been measured from extensive ultraviolet (IUE) observations in a number of sdO stars, which also seem to exhibit a large microt…
Emission from the transition regions and coronae of three cool dwarf stars.
Rego, M.; Fernandez-Figueroa, M. J.; de Castro, E.
An analysis is presented of the outer atmospheres of three cool dwarf stars (Tau Cet, Delta Pav, and 61 Cyg A) observed with the IUE, for which Einstein X-ray observations are available. The ultraviolet emission line fluxes are used to derive the distribution of the emission measure as a function of temperature, and from these distributions the st…
Investigation of IUE spectra of the CP star ET And (HD 219749).
Barylak, M.; Rakos, K. D.
Seventeen IUE spectra of ET And (HD 219749, HR 8861) have been investigated. The rotational velocity as derived by using the Fourier technique is v sin i = 78.8 + or - 9.0 km/sec, which is in good agreement with the values given in the literature. However, there is a large difference between v sin i measurements of photospheric lines and those of …
Psi 3 PISCIUM and the rotation-activity connexion
Williams, D.; Stickland, D. J.
IUE observations of the rapidly rotating G0 III star ψ3 Psc and a number of RS CVn systems, together with data from the literature, have been studied to clarify the relationship between axial rotation and chromospheric activity.
On the stellar content of the galactic globular cluster M 5.
Altamore, A.; Capuzzo-Dolcetta, R.; Angeletti, L. +1 more
New IUE observations of the innermost region of the galactic globular cluster M5 (NGC 5904) are presented and discussed. Addition of IUE spectra and identification of spectral features were obtained from the present and previous IUE observations of M5. Synthetic models of the cluster were constructed by taking into account optical and UV data. A c…
Evidence for outburst in the shell star 17 Lep derived from ultraviolet spectra.
Molaro, P.; Morossi, C.; Ramella, M.
Seven high resolution spectra of the primary of the binary system 17 Lep are analyzed. Variations in the shell lines that dominate the ultraviolet spectrum are found. Two of the spectra show shortward enlargements of the strongest shell lines, reaching a FWHM up to 250 km s-1, and the weakening of the weakest lines. Our suggestion is th…
High resolution ultra-violet observations of alpha Lyrae using the University College London balloon-borne telescope system.
Boksenberg, A.; Welsh, B. Y.; Towlson, W. A. +1 more
Spectral observations at a resolution of 8 km s-1 covering the region 2000 - 3200 Å have been made of the bright star α Lyrae (Vega) using the University College London Balloon-borne Ultraviolet Telescope and Image-tube Spectrograph.
The authors report on the in-flight instrument performance and in particular the sensitivity and re…Search for Gamma Rays of Energies E > 10**15 EV from Discrete Sources
Samorski, M.; Stamm, W.
The data of the extensive air shower experiment at Kiel have been systematically scanned for possible gamma-ray sources in the energy range E > 1015eV and declination range δ = 25° - 75°. Photon fluxes for the six statistically most significant source candidates and 3 σ upper limit photon fluxes for COS B gamma-ray sources are presen…
A study of the binary system 58 Persei.
Stickland, D. J.; Lloyd, C.; Pike, C. D. +3 more
The spectroscopic (and astrometric) binary 58 Persei has been observed at optical wavelengths and with IUE. The system is shown to consist of a mid B-type main-sequence star and a late G-type supergiant at a distance of 320 pc.
Predicted and observed spectrum of M5.
Nesci, R.
From a recently published, statistically complete HR diagram of the globular cluster M5, the number distribution of HB stars as a function of the effective temperature is derived and the bolometric luminosities obtained via the conversion tables by Kurucz (1979). The expected UV energy distribution is then computed and compared with the IUE and OA…