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An Estimation of the Shape and Location of the Heliospheric Termination Shock
Moussas, X.; Exarhos, G.
We calculate semianalytically the distance to the heliospheric termination shock, and we use Ulysses measurements as data input for a realistic application. Therefore, we can find directly the consequences of the solar wind latitudinal variation on the shape of the termination shock. The model that we use is an approximate gasdynamic model. Our pu…
Glitch effects in ISOCAM Long Wave detector
Starck, J. -L.; Claret, A.; Dzitko, H. +1 more
One of the main limitations to the sensitivity of observations carried out with the ISOCAM infrared camera comes from the responsivity variations and glitches caused by impacts of charged particles. After more than 28 months of successful operations, the predicted glitch rate has been re-evaluated and compared to in-flight measurements. Glitch pro…
The Rotation Rate and the Surface Temperature of the Hot, Accreting White Dwarf in the Dwarf Nova RX Andromadae
Szkody, P.; Cheng, F. H.; La Dous, C. +3 more
We obtained Hubble GHRS phase-resolved spectroscopic observations of the dwarf nova RX Andromadae at three times in its outburst cycle: (1) near the end of an extraordinarily deep and long dwarf nova quiescence, 3 months after the last previous outburst; (2) during the rise to outburst; and (3) near the end of a decline from outburst. The spectral…
A thermokinetic study of wave-modulated solar wind electrons using truncated maxwellians
Fahr, H. J.; Chashei, I. V.
Classical kinetic solar wind theories reveal that the solar wind electron distribution function has a delicate influence on the acceleration of the coronal solar wind and its asymptotic velocity. In collisionless kinetics this results from the fact that no hyperbolic electrons with sunward velocities can be expected above the coronal exobase. This…
Quasi-stationary solar wind in ray structures of the streamer belt
Eselevich, M. V.; Eselevich, V. G.
It is shown on the basis of analyzing the LASCO/SOHO data that the main quasi-stationary solar wind (SW), with a typical lifetime of up to 10 days, flows in the rays of the streamer belt. Depending on R, its velocity increases gradually from V≈3 km s−1 at R≈1.3 R⊙ to V≈170 km s−1 at R≈15 R⊙. We have dete…
Numerical Simulations of Trapped Slow Magnetosonic Waves in Solar Coronal Plumes
Ofman, L.; Deforest, C. E.
Recent observations of polar plumes in the southern solar coronal hole by the Extreme ultraviolet Imaging Telescope (EIT) on board the SOHO spacecraft show signatures of quasi-periodic compressional waves. Here, we present the results of a nonlinear, 2D MHD simulation of the slow magnetosonic waves in plumes for typical coronal conditions consiste…
The mass function of NGC 288
De Marchi, G.; Pasquali, A.; Brigas, M. S.
We present NICMOS NIC3 observations of the Galactic globular cluster NGC 288, taken South - East at 2.4 times the cluster's half-light radius in the J and H bands. We have detected the cluster main sequence down to J =~ 25 and H =~ 24. The corresponding luminosity function covers the range 3 < M_H < 9 and peaks at M_H =~ 6.8. The theoretical…
The UV spectra of NLS1s - implications for their broad line regions
Brandt, W. N.; Vestergaard, M.; Mathur, S. +3 more
We study the UV spectra of NLS1 galaxies and compare them with typical Seyfert 1 galaxies and quasars. The NLS1 spectra show narrower UV lines as well as weaker CIV λ1549 and CIII] λ1909 emission. We show that these line properties are due to a lower ionization parameter and somewhat higher BLR cloud densities. These modified conditions can be exp…
Two-dimensional Modeling of the Solar Oscillation l-ν Power Spectrum
Jefferies, Stuart M.; Meunier, Nadège
We describe an algorithm which can accurately model the spatial-temporal l-ν solar oscillation power spectrum over large ranges in frequency (ν) and degree (l). We show how modeling in two dimensions provides a better representation of the observed spectrum than can be obtained with traditional one-dimensional approaches. The gain comes from using…
The IUE and Hubble Space Telescope GHRS Spectrum of the ``Hybrid''/PG 1159-Type Central Star of the Planetary Nebula NGC 7094
Feibelman, Walter A.
Absorption features in the IUE spectrum of the ``hybrid'' PG 1159-type central star of NGC 7094 have been identified and measured. We report equivalent widths for photospheric Fe VI and Fe VII features, interstellar and circumstellar absorptions, and variability of O V λ1371 and C IV λ1549 P Cygni profiles. The terminal wind velocity of -3680+/-30…