Search Publications

Stream interfaces and energetic ions II: Ulysses test of Pioneer results

Gosling, John T.; Intriligator, Devrie S.; Kunow, Horst +2 more

Ulysses measurements of energetic and solar wind particles taken near 5 AU between 20 and 30 degrees south latitude during a well-developed recurring corotating interaction region (CIR) show that the CIR's corotating energetic ion population (CEIP) associated with the trailing reverse shock starts within the CIR at the stream interface. This is co…

Photoionization modelling based on HST images of Magellanic Cloud planetary nebulae - I. SMCN2 and SMCN5

Barlow, M. J.; Blades, J. C.; Liu, X. -W. +2 more

We construct fully self-consistent, detailed photoionization models for two planetary nebulae (PNe) in the Small Magellanic Cloud (SMC), namely SMC N 2 and SMC N 5, to fit optical and UV spectrophotometric observations as well as HST Faint Object Camera (FOC) narrow-band images taken in the light of Hβ. The derived density structure shows that bot…

3-D Distribution of Cosmic Rays in the Outer Heliosphere

Jokipii, J. R.; Kóta, J.

Radial gradients of ion densities and temperatures derived from SWICS/Ulysses observations

Livi, S.; Woch, J.; Marsch, E. +4 more

Mean density and temperature gradients of solar wind protons and α particles are derived from SWICS/Ulysses observations between 1.2 and 5.4 AU in the ecliptic plane during declining solar activity. All parameters are sorted in solar wind speed classes. The radial gradients show a similar behavior for both ion species. In the slow solar wind proto…

Cosmic ray modulation by expanding, high-latitude streams

Keppler, E.; Quenby, J. J.; Drolias, B. +2 more

As ‘Ulysses’ moved to latitudes above 45°, the regular, recurring series of mid-latitude high-speed streams is no longer observed out to 4 AU. However, the associated, near-relativistic particle modulation persists to at least 70°. We explain this remote shadowing as due to the spread in latitude of the fast streams beyond the ‘Ulysses’ trajectory…

Comparison of the main magnetic and plasma features in the environments of comets Grigg-Skjellerup and Halley

Glassmeier, K. -H.; Neubauer, F. M.; Reme, H. +1 more

The successful flyby of Giotto at the weakly active comet P/Grigg-Skjellerup on July 10, 1992 has added a new set of observations to those obtained at the active comet P/Halley in March 1986 for the study of the solar wind - comet interaction. Despite the very different scales of the interaction regions for the two comets (10^6 km for Halley and 1…

IUE observations of blue horizontal branch stars in the globular clusters M 3 and NGC 6752.

Cacciari, C.; Bragaglia, A.; Fusi Pecci, F. +1 more

IUE observations of 3 blue horizontal branch (BHB) stars in M 3 and 4 stars in NGC 6752 are presented. In addition, unpublished IUE archive data have been used for 5 more BHB stars in NGC 6752. Using the most recent model atmospheres (Kurucz 1992) the physical parameters of these stars have been derived, and compared with the ZAHB evolutionary tra…

Rotationally Resolved Studies of the Mid-Ultraviolet Spectrum of Triton. II. HST Surface and Atmospheric Results

Stern, S. Alan; Trafton, Laurence M.; Flynn, Brian

Using the Hubble Space Telescope (HST) we have obtained useful spectra of Triton at a resolution of 2 Å from 1900-3278 Å, at five rotational phases in 1992 and 1993. We present these data and analyze them to evaluate the rotational variability of Triton's mid-ultraviolet reflectance spectrum, albedo, and color slope. The main characteristics of Tr…

HST Images of the Eclipsing Pulsar B1957+20

Fruchter, Andrew S.; Bailyn, Charles D.; Bookbinder, Jay

We have obtained images of the eclipsing pulsar binary PSR~B1957+20 using the Planetary Camera of the Hubble Space Telescope. The high spatial resolution of this instrument has allowed us to separate the pulsar system from a nearby background star which has confounded ground-based observations of this system near optical minimum. Our images limit …

Multifrequency Observations of KAZ 102 during the ROSAT All-Sky Survey

Maraschi, L.; Tanzi, E. G.; Pian, E. +14 more

The bright quasar Kaz 102, which lies in the vicinity of the North Ecliptic Pole, was monitored during the ROSAT All Sky Survey for 121.5 days from 1990 July 30 to 1991 January 25. In the course of the survey, optical photometry with various filters was performed at several epochs, together with UV (IUE) and optical spectrophotometry. The spectral…