Search Publications
New light on UU Sagittae.
Pollacco, D. L.; Bell, S. A.
New V- and I-band CCD photometry and medium-resolution spectroscopy are used to derive the masses and radii accurate to less than 10 percent for the individual components of the eclipsing central star of the planetary nebula Abell 63 - UU Sge. Emission lines from the secondary component and He II and N V absorption features from the primary compon…
New detections of Ly-alpha emission in young galaxies.
Terlevich, Roberto; Terlevich, Elena; Diaz, Angeles I. +1 more
We report IUE observations of two extremely low-metallicity H II galaxies. Ly α emission was detected in both galaxies. Our results confirm previous findings that young or unevolved galaxies exhibit weak or absent Ly α emission combined with a strong UV continuum, and that the Ly α/Hβ ratio and metal content are correlated in the sense that the lo…
On the nature of the blue light in central cluster galaxies.
Fabian, A. C.; Crawford, C. S.
An excess blue component of light, extended over the innermost few kpc, is observed in several central cluster galaxies. Using a combination of blue optical spectra and IUE data, we show that the spectrum of the excess blue light is consistent with both star formation dominated by the light of B5 stars, and power-law spectra with slopes between λ^…
IK Peg : a nearby, short-period, Sirius-like system.
Stickland, D. J.; Kellett, B. J.; Wonnacott, D.
The system IK Peg has been known to be a binary for over 60 years but the secondary has never been identified. The detection of this system in the British Wide Field Camera All-Sky Survey in the EUV has enabled the secondary to be positively identified as a white dwarf. Fits to EUV survey data, the first IUE spectrum, and archival X-ray data indic…
The ionization of the winds from cataclysmic variables without classical boundary layers.
Drew, Janet E.; Hoare, Melvin G.
We have calculated a grid of detailed photoionization models for the stellar winds in non-magnetic cataclysmic variables. In the light of evidence which questions the existence of a classical hot, luminous boundary layer we investigate (i) models with cool, luminous boundary layers or (ii) models with no boundary layer at all, but with a moderatel…
The extended nebulosity in the radio galaxy 3C 227.
Walsh, J. R.; Prieto, M. A.; di Serego Alighieri, S. +1 more
3C 227 (z = 0.085) exhibits one of the more spectacular extended nebulosities to be found among active galaxies at moderate redshifts. The gas can be traced to radial distances of about 100 kpc (H_0_ = 50 km s^-1^ Mpc^-1^). The total [O III] 5007-A luminosity is 2.7 X 10^42^ erg s^-1^, of which at least 50 per cent is radiated from the extended re…
Improved effective temperatures for hydrogen-deficient binary stars.
Jeffery, C. S.; Dudley, R. E.
Effective temperatures are obtained for all four known hydrogen-deficient binary stars, using published and archival photometry and new line-blanketed model atmospheres. These model atmospheres largely resolve the well-known mismatch between the theoretical and observed flux distribution for Upsilon Sgr, although a discrepancy persists at short wa…
ROSAT/IUE discovery of a white dwarf companion to HD 33959C.
Barstow, M. A.; Hodgkin, S. T.; Pye, J. P. +2 more
We report the discovery, from the ROSAT EUV and X-ray all-sky surveys, and from IUE spectra, of a white dwarf (WD) companion to HD 33959C. RE 0515 + 324 is among the 10 brightest EUV sources in the sky in the 100-200 A band. It is also a strong soft X-ray source. IUE observations of candidate objects have revealed a previously uncataloged hot DA W…
The chemical compositions of Algol systems - V. Confirmation of carbon deficiencies in the primaries of eight systems.
Lambert, D. L.; Lemke, M.; Tomkin, J.
We use low-noise CCD spectra of 4267-Å C II line in the spectra of eight Algol-type eclipsing binaries to measure the C abundances of their primaries. A differential LTE analysis of the Algol binaries with respect to single standard stars of the same spectral type shows marginal to moderate deficiencies of C in the primaries of the binaries. We fi…
Optical and ultraviolet observations of the star LkHα 264.
Collier Cameron, A.; Gameiro, J. F.; Lagor, M. T. V. +1 more
We present new ultraviolet and optical data for the classical T Tauri star LkH-alpha 264. The most important features in the UV spectrum are identified and their fluxes are measured. These fluxes are then compared to the corresponding values in the sun and in other T Tauri stars. Our time series of high-resolution spectra for the regions of the H-…