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Radiation-driven winds of hot luminous stars. XIII. A description of NLTE line blocking and blanketing towards realistic models for expanding atmospheres
Pauldrach, A. W. A.; Hoffmann, T. L.; Lennon, M.
Spectral analysis of hot luminous stars requires adequate model atmospheres which take into account the effects of NLTE and radiation driven winds properly. Here we present significant improvements of our approach in constructing detailed atmospheric models and synthetic spectra for hot luminous stars. Moreover, as we regard our solution method in…
EXPORT: Spectral classification and projected rotational velocities of Vega-type and pre-main sequence stars
Rauer, H.; Schneider, J.; Eiroa, C. +19 more
In this paper we present the first comprehensive results extracted from the spectroscopic campaigns carried out by the EXPORT (EXoPlanetary Observational Research Team) consortium. During 1998-1999, EXPORT carried out an intensive observational effort in the framework of the origin and evolution of protoplanetary systems in order to obtain clues o…
High resolution X-ray spectroscopy of zeta Puppis with the XMM-Newton reflection grating spectrometer
Mewe, R.; Güdel, M.; Leutenegger, M. A. +5 more
We present the first high resolution X-ray spectrum of the bright O4Ief supergiant star zeta Puppis, obtained with the Reflection Grating Spectrometer on-board XMM-Newton. The spectrum exhibits bright emission lines of hydrogen-like and helium-like ions of nitrogen, oxygen, neon, magnesium, and silicon, as well as neon-like ions of iron. The lines…
The mass of the neutron star in Vela X-1
Kaper, L.; Telting, J. H.; Barziv, O. +2 more
We measured the radial-velocity curve of HD 77581, the B-supergiant companion of the X-ray pulsar Vela X-1, using 183 high-resolution optical spectra obtained in a nine-month campaign. We derive radial-velocity amplitudes for different lines and wavelength regions, and find all are consistent with each other, as well as with values found in previo…
The ISO-SWS spectrum of planetary nebula NGC 7027
Pottasch, S. R.; Beintema, D. A.; Bernard Salas, J. +1 more
We present the infrared spectrum of the planetary nebula
Time-resolved spectral analysis of the pulsating helium star V652 Her
Jeffery, C. S.; Woolf, V. M.; Pollacco, D. L.
A series of 59 moderate-resolution high signal-to-noise spectra of the pulsating helium star
Helium-like triplet density diagnostics. Applications to CHANDRA-LETGS X-ray observations of Capella and Procyon
Schmitt, J. H. M. M.; Kaastra, J. S.; Burwitz, V. +6 more
Electron density diagnostics based on the triplets of helium-like C v, N vi, and O vii are applied to the X-ray spectra of Capella and Procyon measured with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra X-ray Observatory. New theoretical models for the calculation of the line ratios between the forbidden (f), interc…
Non-axisymmetric accretion on the classical TTS RW Aur A
Tuominen, I.; Gahm, G. F.; Gameiro, J. F. +5 more
High-resolution spectroscopic monitoring of the exceptionally active classical T Tauri star (CTTS) RW Aur A was carried out in three seasons of 1996, 1998 and 1999 with simultaneous B, V photometry. The high quality spectra revealed a multicomponent structure of the spectrum, which includes: 1) a veiled photospheric spectrum of a K1-K4 star, 2) br…
A search for the cause of cyclical wind variability in O stars. Simultaneous UV and optical observations including magnetic field measurements of the O7.5III star xi Persei
Kaper, L.; Bohlender, D. A.; Gordon, K. +13 more
We present the results of an extensive observing campaign on the O7.5 III star
The INES system. IV. The IUE absolute flux scale
Wamsteker, W.; González-Riestra, R.; Cassatella, A
This paper deals with the definition of the input fluxes used for the calibration of the IUE Final Archive. The method adopted consists in the determination of the shape of the detector's sensitivity curves using IUE low resolution observations with model fluxes of the DA white dwarf G191-B2B. A scale factor was then determined so that the IUE obs…