Search Publications
Far-Ultraviolet light curves of the δ Scuti variable: β Cassiopeiae
Cugier, H.; Daszyńska, J.
XMM-Newton high-resolution x-ray spectroscopy of the Wolf-Rayet object WR25 (WN6HA+04F)
Schmutz, W.; Raassen, A. J. J.; Mewe, R. +5 more
We report the analysis of the X-ray spectrum of the Wolf-Rayet star WR 25, observed by RGS and EPIC-MOS on board XMM-Newton. Temperatures up to 40 MK have been determined. Strong absorption, exceeding the value due to the Inter Stellar Medium (ISM) has been detected and assigned to the dense stellar wind.
AD Leonis, (dM3:l5V): Analysis of the x-ray spectrum
Raassen, A. J. J.; Mewe, R.; Audard, M. +3 more
We report the analysis of the X-ray spectrum of AD Leo (dM3.5 V), observed by RGS and EPIC-MOS on board XMM-Newton and by LETGS on board Chandra. From the lightcurve the presence of flaring states and a quiescent part is noticed. Temperatures up to 20 MIA have been determined. A significant increase of the emission measure (EM) at high temperature…
Analysis of a coronal loop on the limb
Martens, P. C. H.; Cirtain, J. W.; Winter, H. D.
The ability to accurately measure the temperature and density of the solar atmosphere is essential to understanding the physical nature of Coronal loops. After data has been corrected to account for cosmic ray incidents on the CCD and instrumental effects, there are additional sources of error that must also be addressed. We applied a correction t…
UV spectroscopy with SOHO
Brekke, P.; Harra, L. K.
The UV spectroscopy from SOHO has provided new and exciting results from a wide range of phenomena observed on the Sun. Determination of plasma parameters such as velocity, density, temperatures, line widths and abundances have provided new physical insight into fundamental problems in solar physics. These include magnetic reconnection, quiet Sun …
UV and EUV observations of stellar coronal structure and activity
Brown, Alexander
Ultraviolet (HST, FUSE) and extreme-ultraviolet (EUVE) observations of stellar coronae and flare-related activity are reviewed, with particular attention being devoted to the coronas information that is obtainable in the ultraviolet but not from the X-ray region. The coronas temperature, density, and emission measure distributions of active stars …
Energetic H/He intensity ratio under solar maximum and solar minimum conditions: Ulysses observations
Lario, D.; Roelof, E. C.; Maclennan, C. G. +3 more
We study the solar cycle variability of the heliospheric energetic proton-to-helium abundance ratios. We use 0.5-1.0 MeV nucleon -1 proton and helium intensities observed by the Ulysses spacecraft at both high and low heliographic latitudes. Ulysses observations show that during solar maximum the 0.5-1.0 MeV nucleon -1H/He in…