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Closure of multi-fluid and kinetic equations for cyclotron-resonant interactions of solar wind ions with Alfvén waves
Marsch, E.
Based on quasilinear theory, a closure scheme for anisotropic multi-component fluid equations is developed for the wave-particle interactions of ions with electromagnetic Alfvén and ion-cyclotron waves propagating along the mean magnetic field. Acceleration and heating rates are calculated. They may be used in the multi-fluid momentum and energy e…
G Ring Particle Sizes Derived from Ring Plane Crossing Observations
Throop, Henry B.; Esposito, Larry W.
The Saturn ring plane crossings in 1995-1996 allowed observers using the Hubble Space Telescope and the W. M. Keck telescope to image the planet's diffuse rings from 0.3 to 2.2 µm at a scattering angle θ ∼ 175°. We calculate the G ring reflectance for size distributions of dust to kilometer-sized bodies derived from a physical, evolutionary …
Pulsation modes of Mira stars and questioning of linear modelling: indications from HIPPARCOS and the LMC
Barthes, D.
Thorough discussion of the previous theoretical works on the pulsation of Long Period Variables leads us to the conclusion that the mode periods predicted by linear models must significantly differ from the reality, and that, if one nevertheless relies upon such a modelling, it is at least necessary to change the mixing length. The hypothesis that…
ORFEUS II Far-Ultraviolet Observations of 3C 273: Interstellar and Intergalactic Absorption Lines
Krautter, Joachim; Bowyer, Stuart; Hurwitz, Mark +7 more
We present the first intermediate-resolution (λ/Δλ = 3000) spectrum of the bright quasi-stellar object 3C 273 at wavelengths between 900 and 1200 Å. Observations were performed with the Berkeley spectrograph aboard the ORFEUS II mission. We detect Lyβ counterparts to intergalactic Lyα features identified by Morris and coworkers at cz = 19,900, 160…
Far-infrared ISOPHOT observations and the energy balance of a quiescent globule
Lemke, D.; Lehtinen, K.; Mattila, K. +1 more
We have observed a quiescent small globule, the Thumbprint Nebula, with the ISOPHOT far-infrared camera at 100 and 200mu m. The observed emission is optically thin thermal emission from dust at a temperature of ~ 14-16K. The energy budget of the cloud is studied by considering the energy input (interstellar radiation field, ISRF), and outputs (sca…
Theoretical Oscillator Strengths for Sr II and Y III, with Application to Abundances in the HgMn-Type Star χ Lupi
Wahlgren, Glenn M.; Proffitt, Charles R.; Brage, Tomas +2 more
Oscillator strengths for selected transitions of Sr II and Y III have been determined using ab initio multiconfiguration Hartree-Fock techniques. The importance of including an accurate treatment of the core-valence correlation is emphasized. The results are used to determine the abundances of Sr and Y in the chemically peculiar star χ Lupi from H…
The Ultraviolet Continuum Emission of Radio Galaxies. I. Description of Sources from the Hubble Space Telescope Archives
Baum, Stefi A.; Zirbel, Esther L.
This paper describes the UV continuum radiation in the range from 1400 to 3700 Å of radio galaxies. The analysis is deferred to the next paper in this series. The sample of radio galaxies was compiled by searching the Hubble Space Telescope (HST) archives for images taken with the Faint Object Camera (FOC) prior to 1993. Altogether the sample cons…
Broad Ne VIII λ774 Emission from Quasars
Hamann, Fred; Cohen, Ross D.; Shields, Joseph C. +3 more
Ne VIII λ774 is an important tracer of the high-ionization gas in QSOs. We examine the Ne VIII emission-line properties using new Hubble Space Telescope (HST)-FOS spectra of four sources, mean spectra derived from two QSO samples in the HST archives, and new photoionization calculations. The results support our previous claim that broad Ne VIII li…
Elemental composition of the January 6, 1997, CME
Hsieh, K. C.; Wurz, P.; Bochsler, P. +25 more
Using solar wind particle data from the CELIAS/MTOF sensor on the SOHO mission, we studied the abundance of the elements O, Ne, Mg, Si, S, Ca, and Fe for the time period around the January 6, 1997, coronal mass ejection event (CME). In the interstream and coronal hole regions before and after this event we found elemental abundances consistent wit…
On the HIPPARCOS photometry of chemically peculiar B, A, and F stars
Adelman, Saul J.
The Hipparcos photometry of the Chemically Peculiar main sequence B, A, and F stars is examined for variability. Some non-magnetic CP stars, Mercury-Manganese and metallic-line stars, which according to canonical wisdom should not be variable, may be variable and are identified for further study. Some potentially important magnetic CP stars are no…