Search Publications
The circumstellar environment of UX ORI
Prusti, T.; Thi, W. F.; Natta, A. +3 more
This paper presents new observations of UX Ori obtained with the millimeter interferometer of Plateau de Bure and with ISO. UX Ori is the prototype of a group of pre-main-sequence, intermediate-mass stars, often indicated as precursors of beta Pic. The interferometry observations at 1.2 and 2.6 mm show that UX Ori has a circumstellar disk, with ou…
Amplitude evolution and rigidity dependence of the 26-day recurrent cosmic ray decreases: COSPIN/KET results
Kunow, H.; Bothmer, V.; Potgieter, M. S. +8 more
In the time interval extending from July 1992 to July 1994, Ulysses climbed from 10°S heliographic latitude up to over 70°S. During this time lapse, solar minimum conditions were gradually approached, which, in turn, led to stable and long-lasting corotating interaction regions (CIRs). The corotating particle events observed during this period, as…
Interstellar oxygen in the heliospheric interface: influence of electron impact ionization
Geiss, J.; Lallement, R.; Izmodenov, V. V.
A fraction of the interstellar atoms crosses the interface between the solar wind and the ionized component of the local interstellar medium (the heliospheric interface), and enters the heliosphere. The number of penetrating atoms depends on the strength of the atom-plasma interaction, i.e. on the atom type. In this paper we consider the penetrati…
Study of the latitudinal dependence of H I Lyman α and O VI emission in the solar corona: Evidence for the superradial geometry of the outflow in the polar coronal holes
Kohl, John L.; Cranmer, Steven R.; Dobrzycka, Danuta +2 more
We study the latitudinal distribution of the H I Lyman α and O VI (103.2 nm and 103.7 nm) line emission during the period of the Whole Sun Month campaign (August 10 to September 8, 1996) when the Sun was close to the minimum of its activity. The H I Lyman α and O VI line intensities appeared to be almost constant with latitude within the polar cor…
Late A-type stars: new Strömgren photometric calibrations of absolute magnitudes from HIPPARCOS
Figueras, F.; Domingo, A.
Hipparcos trigonometric parallaxes have been used to derive a photometric absolute magnitude calibration of main-sequence late A-type stars in terms of Strömgren photometric indices - accounting for temperature, evolution and metallicity effects - and projected equatorial rotational velocities. The derived calibrations are valid for main-sequence …
Non-Uniqueness of Atmospheric Modeling
Judge, Philip G.; McIntosh, Scott W.
We focus on the deceptively simple question: how can we use the emitted photons to extract meaningful information on the transition region and corona? Using examples, we conclude that the only safe way to proceed is through forward models. In this way, inherent non-uniqueness is handled by adding information through explicit physical assumptions a…
Radiation scattering in the solar corona
Noci, G.; Maccari, L.
This paper discusses the scattering in the solar corona of the radiation emitted by the solar disk. We obtain expressions for the emissivity which permit to deduce the spectral characteristics of the scattered radiation. With these expressions, assuming a Maxwellian distribution for the velocities of the scattering ions and a simple spectral shape…
[Fe II] Bubbles in the Young Planetary Nebula Hubble 12
Woodward, Charles E.; Frank, A.; Forrest, W. J. +2 more
We have obtained narrowband images of the young planetary nebula Hubble 12 showing [Fe II] line emission in bipolar bubbles near the core. Bright [Fe II] emission is strong evidence for shocks, suggesting the presence of a high-velocity wind emanating from the central star. We compare our data to previously published images of Hubble 12--finding s…
Quasar host galaxy images from the Hubble Space Telescope Archive
Disney, M. J.; Boyce, P. J.; Bleaken, D. G.
We systematically searched the non-proprietary data in the Hubble Space Telescope (HST) Archive to identify low-redshift quasars that have been imaged with the Wide Field Planetary Camera-2 (WFPC-2) but that have not yet been presented in the literature. We identified five such objects. Since these represent a significant increment to the number o…
Transport and Mixing in Jupiter's Stratosphere Inferred from Comet S-L9 Dust Migration
West, Robert A.; Friedson, A. James; Hronek, Amy K. +2 more
We use a series of 230-nm wavelength images acquired with the Hubble Space Telescope Wide Field and Planetary Camera 2 to trace the spreading of debris introduced into Jupiter's stratosphere by the impact of Comet Shoemaker-Levy 9. Impact debris was transported rapidly equatorward by stratospheric winds from the impact latitude at -45° to at least…