Search Publications
Is There Evidence for Rotation or Horizontal Motions in Hot DB White Dwarfs?
Bergeron, P.; Wesemael, F.; Dufour, P.
In a recent analysis of Goddard High Resolution Spectrograph observations of three hot DB white dwarfs, Provencal et al. suggested that the C II λ1335 doublet in two such objects is abnormally broadened. This was interpreted as the signature of rotation, or perhaps of pulsation-related horizontal motions, at a velocity of v~60kms-1. Our…
A photometric study of the recently discovered eclipsing binary V899 Herculis
Bulut, İ.; Demircan, O.; Soydugan, F. +4 more
The radial velocity and UBV light curves of V899 Her as found in the literature were studied for the first time to obtain the orbital parameters and geometry of the system. The solutions obtained by using the Wilson-Devinney code reveal an over-contact system with a fill-out factor of 23.7%. This solution is only possible with a large amount of th…
The 3 mu m spectrum of R Doradus observed with the ISO-SWS
Ryde, N.; Eriksson, K.
We have modeled the 2.6-3.7 µm spectrum of the red semiregular variable R Doradus observed with the Short-Wavelength Spectrometer on board the Infrared Space Observatory. The wavelength resolution of the observations varies between R ~ 2000-2500. We have calculated a synthetic spectrum using a hydrostatic model photosphere in spherical geome…
Artifacts at 4.5 and 8.0 Microns in Short-Wavelength Spectra from the Infrared Space Observatory
Price, S. D.; Sloan, G. C.; Kraemer, K. E.
Spectra from the Short-Wavelength Spectrometer (SWS) on board the Infrared Space Observatory exhibit artifacts at 4.5 and 8 µm. These artifacts appear in spectra from a recent data release, OLP 10.0, as spurious broad emission features in the spectra of stars earlier than approximately F0, such as α CMa. Comparison of absolutely calibrated s…
Interstellar Extinction Along the Camelopardalis and Perseus Border
Zdanavičius, J.; Zdanavičius, K.
Interstellar extinction in a ~ 100 sq. degree area at the Camelopardalis and Perseus border is investigated. The study is based on the results of photoelectric photometry of 455 stars in the seven-color Vilnius photometric system published earlier. The nearest 100 stars with Hipparcos parallaxes show that the extinction starts to grow at a distanc…
XMM-Newton Spectroscopy of the Galactic Microquasar GRS 1758-258 in the Peculiar Off/Soft State
Wijnands, R.; Miller, J. M.; Lewin, W. H. G. +5 more
We report on an XMM-Newton Reflection Grating Spectrometer observation of the black hole candidate and Galactic microquasar GRS 1758-258. The source entered a peculiar ``off/soft'' state in 2001 late February in which the spectrum softened while the X-ray flux-and the inferred mass accretion rate-steadily decreased. We find no clear evidence for e…
Radio observations of super star clusters in dwarf starburst galaxies
Forbes, Duncan A.; Stevens, Ian R.; Norris, Ray P.
We present new radio continuum observations of two dwarf starburst galaxies, NGC 3125 and 5408, with observations at 4.80 GHz (6 cm) and 8.64 GHz (3 cm), taken with the Australia Telescope Compact Array (ATCA). Both galaxies show a complex radio morphology with several emission regions, mostly coincident with massive young star clusters. The radio…
The Near-Nuclear Coma of Comet Halley in March 1986
Fulle, Marco; Szegö, Karoly; Crifo, Jean-François +1 more
The cameras carried onboard the flyby missions to comet P/Halleyin 1986 imaged the near nuclear jet activity fromseveral spatial directions. The observed, very structured near nucleardust jets were considered at that timeas the result of dust emission from well localized active surface regions(without supporting 3-D model computations, however).Ba…
FUSE observations towards the pole-on Be star HR 5223
Frémat, Y.; Zorec, J.; Ferlet, R. +5 more
New spectra have been obtained for the pole-on Be star HR 5223 (HD 120991) using the Far Ultraviolet Satellite Explorer (FUSE). We give a complete description of the far-UV spectral range (920 to 1180 Å). The spectra are affected by strong blends with interstellar lines and molecular bands that also significantly lower the energy distribution of t…
Infrared light curves and absolute stellar parameters of the Algol system δ Librae: is δ Librae really an overmassive Algol binary?
Claret, A.; Arevalo, M. J.; Lazaro, C.
We present the first infrared (IR) light curves in the J, H and K bands of δ Lib obtained at different observing runs from 1994 to 1998. These IR light curves, showing a secondary minimum much deeper than in visual bands, have been analysed in order to determine a new set of physical parameters. A new program using the Roche geometry, and stellar …