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Observations of Saturn's Ribbon Wave 14 Years after Its Discovery
Sanchez-Lavega, Agustín.
A singular feature in planetary atmospheres, the saturnian midnorthern latitude "ribbon" wave, was discovered in images obtained during the Voyager 1 and 2 encounters with the planet in 1980 and 1981. Here we present evidence of its first detection 14 years later (about half a Saturn year later) using archived Hubble Space Telescope images. The pr…
Speckle Observations of Composite Spectrum Stars with PISCO in 1993-1998
Festou, M. C.; Arnold, L.; Scardia, M. +8 more
We present speckle interferometry observations of 47 composite spectrum stars obtained between 1993 and 1998 at the Pic du Midi Observatory with the PISCO speckle camera. 76% of over 150 independent 10 minute sequences of observations led to a companion detection. Binary component angular separations ranged from 0.05" to 1.2". We also obtained a s…
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…