Search Publications
Eclipses in the symbiotic system CH CYG
Bode, M. F.; Skopal, A.; Lloyd, H. M. +1 more
In this Letter we describe observational evidence of eclipses which strongly suggest that CH Cyg is a triple system with a very high inclination. We present U and V photoelectric photometry, along with optical and ultraviolet low- and high-resolution spectroscopy taken around the inferior spectroscopic conjunctions of the red giant in the symbioti…
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 …
The tilts of corotating interaction regions at midheliographic latitudes
Riley, Pete; Gosling, J. T.; Pizzo, V. J. +1 more
Previous analysis of midlatitude corotating interaction regions (CIRs) observed by Ulysses in the southern heliosphere has revealed that the flow downstream of the forward (F) shock (or wave) on the leading edge of a CIR generally turns northward and into the direction of planetary motion (westward), while the flow downstream of the reverse (R) sh…
The Ultraviolet and X-Ray View of the Demise of Nova V1974 Cygni
Sonneborn, G.; Shore, Steven N.; Starrfield, Sumner
We present new data on the variations of the ultraviolet nitrogen lines during the late, optically thin stages of the outburst of V1974 Cygni. These show that, ~500 days after discovery, the ejecta reached maximum ionization and then started to recombine, coincident with the X-ray turnoff observed with ROSAT. We derive densities for the ejecta at …
The Translucent Molecular Clouds toward HD 154368. I. Extinction, Abundances, and Depletions
Snow, Theodore P.; van Dishoeck, Ewine F.; Black, John H. +5 more
We report the results of a comprehensive analysis of a line of sight observed using the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST), toward HD 154368, an 09.5 lab star located about 800 pc away. The line of sight intersects translucent interstellar cloud material, having a color excess E(B - V) = 0.82 and known …
Combined Ultraviolet-Optical Spectropolarimetry of the Magnetic White Dwarf GD 229
Liebert, James; Schmidt, Gary D.; Smith, Paul S. +1 more
Detailed flux and polarization spectra of the magnetic white dwarf GD 229 have revealed a host of new absorption features in the ultraviolet and rich detail in the polarization of the strong optical lines. However, hydrogen does not appear to be represented in the spectrum. Thus, the many peculiar features still elude identification, and the magne…
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…
Properties of Star 2, One of the SN 1987A Companions, Derived from Hubble Space Telescope--Faint Object Spectrograph Observations
Panagia, N.; Kirshner, R. P.; Gilmozzi, R. +2 more
We present and discuss the Hubble Space Telescope Faint Object Spectrograph observations of Star 2, one of the two companions of SN 1987A, in the range 1200-8000 A. Our analysis, based on a comparison of the observed spectrum with spectra of O and B type stars and with model atmospheres, confirms that Star 2 is a B2III star. The extinction toward …
Origin of C+ ions in the heliosphere
Geiss, J.; Gloeckler, G.; von Steiger, R.
C+ pickup ions were investigated with the SWICS instrument along the trajectory of Ulysses, covering a broad range of solar latitude and distance. Whereas nearly all the observed H+, He+, N+, O+ and Ne+ pickup ions are created from the interstellar gas penetrating deep into the heli…
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…