Search Publications
The graphite rich Cepheus OB3 association.
Panagia, N.; Perinotto, M.; Barsella, B.
The four optically brightest stars of the Cepheus OB 3 association have been observed with the IUE satellite in the spectral range 1150-3200 A. The extinction suffered by the stars has been investigated. Both the shape of the bump at approximately 2200 A and the behavior of the extinction at longer wavelengths are close to those of the mean inters…
UV, optical and IR observations of cepheid R Mus.
Heck, A.; Russo, G.; Eichendorf, W. +2 more
Ultraviolet IUE spectra, optical 12 A/mm red and blue spectra, optical BV photometry and infrared JHKL photometry of the 7.5-d classical Cepheid R Muscae equals HD 110 311 are presented and discussed together with some earlier photometric and radial velocity data. Using the CORS method, a newly derived radius is given, as well as new values for ef…
A search for medium Z elements in the ultraviolet spectrum of kap Cnc.
Bord, D. J.; Davidson, J. P.
The method of wavelength coincidence statistics is used to search for selected elements having Z values in the 12-40 range in the long wavelength (1960-3230 A) IUE spectrum of the Hg-Mn star Kappa Cancri. Evidence to support the identifications of the even Z elements Mg, Si, Ca, Sr, and Zr, in addition to the odd Z element Cl, has been found. Resu…
The visible and ultraviolet continuum from a Herbig-Haro object in the core of M 16 (NGC 6611).
Meaburn, J.
A Herbig-Haro object was found by Meaburn and White (1982) in the neutral clouds within the galactic H II region M 16. Two IUE spectra have now been obtained of this in which a strong continuum is present but no emission lines found. The continuum around 6670 A appears to be of atomic recombination origin but the evidence favors the interpretation…
An alternative procedure for extracting IUE low resolution spectra.
Morossi, C.; Crivellari, L.
This paper presents an alternative procedure which extracts spectra from IUE low resolution images. The -by-line image is scanned perpendicularly to the direction of dispersion . The resulting cross-cuts are then fitted with a known-form analytical function, which consists of a linear base-line describing the background plus as many bands as there…
The outer atmosphere structure of three late type stars.
Rego, M.; Fernandez-Figueroa, M. J.; de Castro, E.
Far ultraviolet emission lines of three late type stars, two dwarfs (chi Her and beta Com) and one subgiant (Iota Vir), have been analysed to determine the structure of their outer atmospheres. Emission line fluxes are used to find the emission measure distributions. Using three boundary values of the electron pressure, calculated in a previous pa…
On the ionization and velocity structure of expanding circumstellar envelopes.
Drechsel, H.; Rahe, J.
It is shown that the envelope line profiles formed by the scattering of stellar continuum flux in expanding atmospheres of luminous, early-type and Wolf-Rayet stars are sensitive to the variation of (1) the optical depth in the line, and (2) the velocity gradient of the stellar wind, as a function of radial distance from the star. A theoretical pr…
The far-UV spectrum of the low-excitation planetary nebula HD 138403.
Surdej, J.; Heck, A.
Two high-resolution far-UV spectra of the low-excitation planetary nebula HD 138403 are analyzed which were obtained with the IUE satellite over the wavelength range from 1170 to 2070 A. It is shown that the nebula's far-UV spectrum comprises a stellar continuum on which are superimposed a few emission lines, numerous interstellar absorption lines…
Star formation and extinction in extragalactic H II regions.
Kunth, D.; Deharveng, J. M.; Lequeux, J. +1 more
Evolutionary models are presented of far UV luminosity, production of ionizing photons, effective temperature, and ejection of heavy elements for an ionizing star cluster. The way in which interstellar extinction in our Galaxy and inside and outside the H II region affects the UV and optical emission of the complex is discussed. Conclusions are de…
3C 273 revisited : confirmation by COS-B of high energy gamma-ray emission.
Caraveo, P. A.; Bignami, G. F.; Hermsen, W. +11 more
The results of a second observation in the Virgo region by the ESA COS-B satellite are presented. The presence of a high- energy (50-800 MeV) gamma-radiation source is confirmed, and its position is consistent with 3C273. The error box at the 90% confidence level containing the quasar is ∼2.5 square degrees, and the probability of a chance coincid…