Search Publications
ORFEUS II and IUE Spectroscopy of EX Hydrae
Mauche, Christopher W.
Using five high-resolution (λ/Δλ~3000) FUV (910-1210 Å) spectra acquired in 1996 December during the flight of the ORFEUS-SPAS II mission, 47 archival IUE short-wavelength UV (1150-1950 Å) spectra, and archival EUVE deep survey photometry (70-200 Å), we present a detailed picture of the behavior of the magnetic cataclysmic variable EX Hydrae in th…
Final Astro-2 Calibration of the Hopkins Ultraviolet Telescope
Brown, Thomas M.; Kriss, Gerard A.; Davidsen, Arthur F. +3 more
We present the final calibration of the Hopkins Ultraviolet Telescope (HUT) for its flight during the Astro-2 space shuttle mission in 1995 March. Aspects of mission operations and instrument performance that affect data quality are described in detail, as are the data reduction procedures applied to the archived data. The sensitivity calibration …
Vertical motion and expansion of the Gould Belt
Comerón, F.
The kinematics of the Gould Belt is considered taking into account its orientation in space and the motions of its member stars parallel and perpendicular to the galactic plane. An analysis of Hipparcos data for these stars, complemented with published radial velocities, shows that there is a mild gradient along the galactic plane in the velocity …
The visual orbit of HD 98800
Tokovinin, A. A.
A family of possible visual orbits is computed for HD 98800AB, a young quadruple system of red dwarfs with a dusty disk. Published visual measurements, the radial-velocity difference, and an estimate of the sum of the component masses are used. Orbits with eccentricities from 0.3 to 0.6 and periods from 300 to 430 years result in dynamical paralla…
Two-Temperature Coronal Models from SOHO/EIT Observations
Zhang, J.; Kundu, M. R.; White, S. M.
We present a method for deriving a two-thermal-component approximation to the differential emission measure distribution of plasma in the Sun's corona in the temperature range to which the Extreme-Ultraviolet Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) spacecraft is sensitive. EIT takes high-resolution full-disk corona…
Ammonia and Eddy Mixing Variations in the Upper Troposphere of Jupiter from HST Faint Object Spectrograph Observations
Simon, A. A.; Edgington, S. G.; Atreya, S. K. +4 more
Ultraviolet spectra of the northern and southern hemispheres of Jupiter taken with the Hubble Space Telescope Faint Object Spectrograph (FOS) in May 1992 and June 1993 have been used to derive the altitude profiles of NH 3 in the vicinity of the tropopause. For a given pressure level, it is shown that the vertical profile of ammonia var…
ISO spectroscopy of shocked gas in the vicinity of T Tauri
Spinoglio, L.; van Dishoeck, E. F.; Tielens, A. G. G. M. +2 more
We present the results of ISO SWS and LWS spectroscopy of the young binary system T Tau. The spectrum shows absorption features due to H_2O ice, CO_2 ice, gas-phase CO and amorphous silicate dust, which we attribute to the envelope of T Tau S. We derive an extinction of A_V = 17.4m +/- 0.6m towards this source. Detected emission lines from H i ari…
Dust Lanes Causing Structure in the Extended Narrow-Line Region of Early-Type Seyfert Galaxies
Rieke, G. H.; Alonso-Herrero, A.; Quillen, A. C. +3 more
We construct near-infrared to visible broadband NICMOS/WFPC color maps for four early-type Seyfert galaxies with S-shaped or one-sided ionization cones. We find that dust lanes are near or connected to many of the features seen in the [O III] and Hα + [N II] line emission maps. This suggests that much of the structure of line emission in these ion…
A Large H I Shell surrounding the Wolf-Rayet Star HD 191765
St-Louis, Nicole; Gervais, Simon
We have surveyed a 2.6dx2.6d field centered on the Wolf-Rayet (W-R) star HD 191765 (=WR 134) in the H I 21 cm line and in the 1420 and 408 MHz radio continuum, using the Synthesis Telescope of the Dominion Radio Astrophysical Observatory, to search for direct evidence of the interaction between the W-R star wind and the interstellar medium. An arc…
HUBBLE SPACE TELESCOPE Images of the Compact Nebula around RY Scuti
Smith, Nathan; Gehrz, Robert D.; Humphreys, Roberta M. +3 more
We present HST Wide Field Planetary Camera 2 images of the very massive eclipsing binary RY Scuti. The HST Hα image shows a very complex ionized nebula roughly 1" in size. Several interesting structures are revealed, including what appears to be a pair of concentric ionized rings above and below the equatorial plane of the system, located at the i…