Search Publications
Spatially resolved spectroscopy of WR ring nebulae. II. M 1-67.
Smith, L. J.; Esteban, C.; Manchado, A. +1 more
Detailed, high spatial resolution spectroscopy of the WR ring nebula M1-67 surrounding the WN 8 star WR 124 is presented. Abundances for 4 positions in M1-67 are derived and it is found that N is enhanced by a factor of 4 - 7.5, O is deficient by a factor of 5 - 7.5 and S has a normal H II region abundance. This remarkable abundance pattern leads …
EXOSAT observations of Cygnus X-1 : study of the soft X-ray excess.
Hasinger, G.; Balucinska, M.
The paper presents results of a spectral analysis of the Cyg X-1 data collected during 1984-1985 by the Medium Energy instrument onboard the Exosat satellite. Emphasis is on two issues: the soft X-ray excess in the range below 3 keV and the iron-line intensity. The presence of a soft component in addition to the high-energy power-law component is …
NLTE-analysis of sublimous O stars : KS 292.
Rauch, T.; Werner, K.; Heber, U. +2 more
High-resolution spectra of the southern Galactic sdO star KS 292 are analyzed using modern NLTE model atmospheres in order to determine the atmospheric parameters. The results indicate that KS 292 probably belongs to a newly discovered group of post-AGB stars which are characterized by effective temperatures and gravities typical for central stars…
An IUE and optical study of interstellar gas towards stars within the Cygnus OB1 and OB3 associations.
Smith, L. J.; St. -Louis, N.
The interstellar absorption lines formed towards 13 members of the Cyg OB1 and OB3 associations were examined in detail using IUE and optical spectra. Low (0 to +17 km/s), intermediate (-24 km/s), and high (-40 to -70 km/s) velocity components were detected toward most of the stars. It is found that the main component of the highly ionized species…
The Spacela-1 very wide field survey of UV-excess objects. II. Analysis of 7 stars of various nature.
Deleuil, M.; Bouchet, P.; Prevot, L. +2 more
Multiwavelength observations of seven stellar objects with strong UV excesses are presented. The observations are IUE spectrophotometry, Stromgren Vuvby optical photometry, Johnson JHK infrared photometry, intermediate resolution optical spectroscopy, and in one case a CORAVEL radial velocity survey. Three of the objects are field subdwarfs (one o…
The nebular stage of nova PW Vulpeculae.
Snijders, M. A. J.; Andreae, J.; Drechsel, H. +1 more
UV and optical nebular spectra of Nova PW Vul were used to derive plasma parameters of the ejected shell. From the visual lightcurve decay times of t2 = 83 days and t3 = 147 days are estimated, which indicate that PW Vul is a slow nova. A color excess of E(B - V) = 0.55 and a distance of about 1.3 kpc were derived. Emission line fluxes were deredd…
Oscillator strengths for Y III and Zr III in the IUE region
Redfors, A.
Oscillator strengths for Y III and Zr III in the region 1190-3100 A have been calculated for transitions from all levels below 13 eV. The presence of these spectra in IUE observations of chemically peculiar stars is discussed.
A study of the flaring and quiscent X-ray and UV emission from II Pegasi.
Tagliaferri, G.; White, N. E.; Doyle, J. G. +3 more
An investigation has been conducted of the rotational modulation of the transition-region UV and coronal X-ray emission for the RS CVn system II Pegasi. The X-ray light curve is dominated by a strong flare detected at orbital phase, where the minimum of the photometric wave occurred. The flare parameters derived show that the flare originates with…
Stellar wind properties of A-type hypergiants.
Stahl, O.; Wolf, B.; Smolinski, J. +1 more
The visually bright objects from the Magellanic Clouds are examined in terms of observed properties that indicate properties relevant to the stellar wind. IUE observations are accomplished in the long-wavelength primary echelle mode in the optical wavelength near H-alpha of the objects HD 33579 and HD 7583. The Fe-II lines are found to have widths…
Comet P/Halley's dust production rate at Giotto encounter derived from Halley Multicolour Camera observations
Keller, H. U.; Thomas, N.
Optical constants for the dust from Comet P/Halley have been determined from Halley Multicolour Camera observations by applying the dust size distribution and the total mass impacting the Giotto spacecraft. The quantity of dust is found to be 0.080 rho exp 2/3 where rho is the dust particle bulk density in g/cu cm at an effective wavelength of 653…