Search Publications

Search for X-ray flares in the Pleiades using SoHO LASCO C3 images.

Andrews, A. D.

The detection threshold on LASCO C3 images was examined using the Pleiades cluster. It was found that 100 Pleiades stars to V = 10 were easily identified, and that some stars 4 magnitudes fainter than this could be detected. The brightness of the stellar corona at X-ray wavelengths, especially of active flare stars, may be the explanation for the …

Crowded Field Photometry of M15 Using the TRIFFID Camera

Butler, R. F.; Redfern, R. M.; Shearer, J. A. L.

High-resolution imaging has been performed for a number of years using TRIFFID, the UCG/DIAS High Resolution Camera. Post-exposure image sharpening (PEIS) of TRIFFID data routinely produces resolution improvements up to the theoretical maximum factor of two. HST resolution remains superior but unlike TRIFFID it cannot be used for extended observat…

Spectroscopy of B Stars in the Small and Large Magellanic Clouds

Rolleston, W. R. J.

High-resolution spectroscopic observations of B-type stars in the Small (SMC) and Large (LMC) Magellanic Clouds have been obtained using the UCL echelle spectrograph at the Anglo-Australian Telescope. Preliminary results of an LTE model-atmosphere analysis are presented for three stars in the LMC, together with the results of a similar analysis of…

Effect of interstellar absorption on the MG II H & K profiles and fluxes of RS CVn stars

Doyle, J. G.; Houdebine, E. R.; Butler, C. J.

Tuned Solar and Stellar Oscillations?

Doyle, J. G.; Andrews, A. D.

Giant Starspots and Stellar Flares: The View from Space

Byrne, Patrick B.

Satellite observations of starspots and stellar flares are examined. The properties of sunspots and solar flares are reviewed and the method used to infer the existence of starspots is described. IUE observations of the atmospheres of spotted stars and Exosat X-ray observations of solar flares are discussed. Also, an IUE spectrum of II Peg and a U…

Ireland's contribution to deep space missions

McKenna-Lawlor, Susan M. P.

Irish contributions to the Giotto mission, the Phobos mission, and the planned International Solar Terrestrial Physics (ISTP) program are discussed. Results are presented from the Energetic Particle Onset Admonitor (Epona) experiment, which flew on the Giotto mission. The Epona instruments detected electrons, protons, alpha particles, and pickup i…

Exploration of the Dust Environment of the Inner Coma of Comet Halley

McDonnell, J. A. M.

Observations of the dust environment of Comet Halley obtained with Giotto, Vega, Susuei, and Sakigake spacecraft are presented and analyzed. Optical/IR, interplanetary space environment, flux and composition, and dynamics and trajectories experiments were conducted. The relation between the dust environment of comets and meteoroid streams is discu…

Empirical Constraints on the Outer Atmospheres of Late-Type Giant Stars with IUE

Judge, P. G.

Useful constraints on the outer atmospheric structure of late-type giant stars can be obtained using emission lines observed with the IUE satellite if all important processes in the atomic excitation calculations are included. Carpenter et al. (1985) did not include such effects, and therefore overestimated the geometric extent of the emission reg…

The Bright Pre-main Sequence Variable HR5999

Talavera, A.; Mewe, R.; Catala, C. +7 more

A meeting to review the reduced coordinated observations by EXOSAT, IUE and ground-based instruments of the bright and variable Herbig A7e star HR 5999 is summarized. The attempt was to delineate the relationship between the various observable quantities of its atmosphere (colors, emission-line fluxes, wind velocities, etc.) in order to develop a …