Search Publications
High resolution spectroscopy of symbiotic stars. II. RW Hydrae: orbit, eclipses, and stellar parameters.
Schmutz, W.; Schild, H.; Muerset, U.
With IUE spectra and published optical photometry, we show that the symbiotic star RW Hya is an eclipsing binary. We use a series of high resolution optical spectra to determine the orbital elements and basic parameters of the stellar components in the system. We measure the orbital velocity amplitude of the red star and determine the binary mass …
Elemental abundances in normal late-B and HgMn stars from co-added IUE spectra. IV. Gallium.
Smith, K. C.
An analysis is presented of the ultraviolet gallium resonance lines in International Ultraviolet Explorer (IUE) spectra of 40 normal, superficially normal, and HgMn-type late-B stars. Gallium abundances are derived by fitting the GaIIλ1414, and GaIIIλλ1495, 1534 lines with synthetic spectra computed under the conventional assumptions of local ther…
The ISO-SWS spectrum of P Cygni.
Waters, L. B. F. M.; Hillier, D. J.; Kudritzki, R. P. +8 more
The free-free IR excess and the IR emission lines of H and He I of the Luminous Blue Variable P Cygni are observed with the ISO-SWS instrument. The observed profiles and the free-free emission are compared with predictions from a non-LTE model atmosphere with a stellar wind. The observations agree very well with a model that has the following prop…
LWS-spectroscopy of Herbig Haro objects and molecular outflows in the Cha II dark cloud.
Ade, P. A. R.; Liseau, R.; White, G. J. +34 more
We present the first far infrared spectra of the Herbig Haro objects HH 52-53-54 and of IRAS 12496-7650, all located in the nearby star forming region known as Chamaleon II dark cloud, obtained with the Long Wavelength Spectrometer (LWS) onboard the Infrared Space Observatory (ISO). The richest spectrum is found in HH 54, showing molecular transit…
HST and groundbased observations of the `Hubble-Sandage' variables in M 31 and M 33.
Stahl, O.; Davidson, K.; Humphreys, R. M. +4 more
The small group of peculiar stars known as the Hubble-Sandage variables in M 31 and M 33 belong to the class of stars we now call the Luminous Blue Variables - highly unstable, evolved massive stars found in many spiral and irregular galaxies. We have used the Hubble Space Telescope to obtain UV imaging and spectroscopy of several of the LBVs in M…
Photoionization resonances of SiII in stellar spectra.
Lanz, T.; Artru, M. -C.; Hubeny, I. +1 more
We have studied the influence of the Si^+^ photoionization on stellar atmospheres. Recent calculations using the R-matrix code provide detailed cross-sections with autoionization resonances for the first 50 energy levels of Si^+^. These photoionization cross-sections are included in the calculation of the far ultraviolet synthetic spectrum of A an…
New X-ray sources detected among mild barium and S stars.
Schmitt, J. H. M. M.; Jorissen, A.; Ginestet, N. +2 more
We report on the detection by ROSAT of X-rays from the mild barium star HD 165141 (K0III/IIBa1) and from the S stars HD 35155 (S4,1) and HR 363 (S3/2). For the S stars, the X-ray flux is attributed to the accretion of the red-giant wind by the white dwarf companion. The strong variability observed in the X- and UV fluxes on time scales of both hou…
LWS observations of the colliding galaxies NGC 4038/39.
Malkan, M. A.; Ade, P. A. R.; Miles, J. W. +31 more
Infrared Space Observatory (ISO) Long Wavelength Spectrometer (LWS) and ground-based Fabry-Perot imaging spectroscopic observations are used to penetrate the extinction to the powerful burst of star formation that has occurred in the extranuclear molecular cloud complex in the galaxy overlap region of the galaxies NGC 4038/39 ("The Antennae"). Par…
NGC 5195 - a look into the hot dusty ISM of an interacting SB0 galaxy with ISOCAM.
Altieri, B.; Okumura, K.; Sauvage, M. +8 more
We present broad-band images and a CVF spectrum of NGC 5195, the companion of M51. NGC 5195 appears as a very strong point source while its spectrum is dominated by the so-called PAH features at 6.2, 7.7, 8.6, and 11.3µm. No hot continuum is detected longward of 14µm, and infrared ionic lines are absent from the spectrum. We examine in…
DA white dwarfs in pointed observations from the ROSAT archive.
Wolff, B.; Jordan, S.; Koester, D.
87 pointed PSPC (Position Sensitive Proportional Counter) observations of hot DA white dwarfs, available in the ROSAT public archive until the end of 1994, have been analyzed together with Wide Field Camera (WFC) and EXOSAT data. From the 57 objects with a significant count rate half of the objects have a temperature below 38,000K and a virtually …