Search Publications
IRAS 03201+5459: a C-rich AGB star with silicate absorption
Szczerba, R.; Jiang, B. W.; Deguchi, S.
IRAS 03201+5459 is a late-type star with a circumstellar envelope according to its IRAS color. It has no identification at optical or near-infrared wavelengths. A full ISO-SWS spectrum between 2.3 and 43 mu m was taken at a resolution of about ~ 300 to investigate its nature. The spectrum shows the 9.7 mu m feature in absorption, usually seen in O…
No QPO time lags from Sco X-1 as seen with EXOSAT: a comparison with Cyg X-2
Kuulkers, Erik; van der Klis, Michiel; Lamb, Frederick K. +2 more
We have measured the phase-delay and rms amplitude spectra of Cyg X-2 and Sco X-1. Using EXOSAT data from the normal branch of Cyg X-2 we confirm earlier (Ginga) results, showing that at an energy near 6 keV there is both a minimum in the quasi-periodic oscillations QPO rms amplitude spectrum and a 150deg phase jump in the QPO phase-del…
Long-duration cosmic ray modulation from a Sun-Earth L1 orbit
Harrison, R. A.; Pike, C. D.
We analyse cosmic ray hits impacting the detector system of the Coronal Diagnostic Spectrometer aboard the Solar and Heliospheric Observatory spacecraft. These observations allow us to study the modulation of cosmic rays over a 4 year period (1996-2000) running from solar minimum to maximum, from a Sun-Earth L1 Lagrangian orbit. The modulation, at…
A spectroscopic study of the magnetic CP-star HR 1094
Wahlgren, G. M.; Nielsen, K.
The chemically peculiar star
The linear force-free field in a spherical shell using a new method to determine the coefficients of the eigenfunction expansion
Bromage, B. J. I.; Clegg, J. R.; Browning, P. K. +2 more
The linear force-free field of a plasma in between spherical shells is found allowing for inhomogeneous boundary conditions. A three-dimensional solution is found by analysis and used as a benchmark to test a solution in terms of an expansion of eigenfunctions where the coefficients are determined by a new method. Alternative methods are also appl…
Possible emission lines from the gaseous beta Pictoris disk
Feldman, P. D.; Lecavelier des Etangs, A.; Ferlet, R. +6 more
We present the results of exploratory HST observations to detect the emission lines of ions in the beta Pictoris disk with the spectrograph slit placed off the star. Possible emission lines from Fe II have been detected at ~10-14erg cm-2 s-1 at 0.5'' from beta Pictoris, which would suggest a total Fe II density of …
Blue stragglers in open clusters. Part II
Drilling, J. S.; Andrievsky, S. M.; Schönberner, D.
We present the results of a spectroscopic study of blue straggler and main sequence B and A - type stars in the open clusters NGC 3496, NGC 6475, NGC 6633 and IC 2602. A detailed analysis based on Kurucz's atmosphere models showed that the main sequence stars rotate rather rapidly and differ from a normal (solar) metallicity for only a few light e…
A unified image of dust grains for the warped spiral galaxy in the merger Centaurus A
Sauvage, M.; Block, D. L.
A unified view of dust grains of all sizes and temperatures in Centaurus A has been generated by combining ISOCAM mid-infrared images with optical data. In our unified V-15mu m ratio image, a symmetrical bar-like structure and spiral arms of size 1.5 kpc surround the nucleus. We have overlaid the (H-K) model colour map of \cite{quillen93} and find…
Simulation of resonance scattering helioseismometer signals from spatially resolved images: Application to the GOLF instrument on SOHO
Henney, C. J.; García, R. A.; Ulrich, R. K. +3 more
A step in the analysis of the data from the GOLF (Global Oscillations at Low Frequency) instrument on SOHO (SOlar and Heliospheric Observatory, an ESA/NASA Mission) involves the calculation of the sensitivity of the GOLF signal to the velocity at each point on the solar surface. A successful model of this sort will permit the intercomparison of da…
Transition region and coronal structuring
Mathioudakis, M.; Keenan, F. P.; Phillips, K. J. H. +3 more
In this paper we examine regions of internetwork, network and bright network emission, observed in the quiet Sun with the Coronal Diagnostic Spectrometer (cds) onboard SoHO. The slopes of the emission measure distributions, between 5.4 <= log Te <= 6.0, are found to differ in each region, suggesting the presence of different atmos…