Search Publications
Merging 4 spacecraft data: concepts used for analysing discontinuities
Glassmeier, K. -H.; Dunlop, M. W.; Southwood, D. J. +2 more
Shocks and discontinuities in space plasmas have received much attention in both theoretical studies and spacecraft data analyses. The advent of multi-spacecraft missions, such as ISEE, have provided for a vast improvement of experimental information available on these structures. The ESA CLUSTER, multi-spacecraft mission presents the community wi…
A White Dwarf Companion to the B5 V Star HR 2875 (y Puppis)
Vennes, Stéphane; Christian, Damian J.; Berghöfer, Thomas W.
An extreme-ultraviolet source in the EUVE and ROSAT Wide Field Camera catalogs, also identified with a very soft ROSAT PSPC X-ray source, is coincident with the B5 V star HR 2875 (y Pup). We present an analysis of PSPC and EUVE spectra revealing the presence of a hot white dwarf companion to HR 2875, which then constitute the first confirmed B sta…
Impact Mechanics and Frequency of SL9-Type Events on Jupiter
Ahrens, Thomas J.; Roulston, Mark S.
A semianalytic model for the breakup of fragments of Comet Shoemaker-Levy 9 upon entry into Jupiter's atmosphere is presented. The model assumes that the impacting fragments behave as bodies of viscous fluid and that the dominant process in their breakup is the growth of hydrodynamic instabilities. It is shown that the size of the smallest instabi…
Solar modulation of galactic cosmic rays: the 3D heliosphere
Heber, Bernd; Potgieter, Marius S.; Ferrando, Philippe
The cosmic ray flux observed with the Kiel Electron Telescope onboard the Ulysses space probe varies with solar activity as well as with heliospheric position. The Ulysses' fast latitude scan performed in less than one year between September 1994 to August 1995 allowed us to obtain unique data about the latitudinal dependence of cosmic ray fluxes …
A Determination of The Nuclear Size of Comet Hale–Bopp (C/1995 O1)
Sekanina, Z.
The signal of the nucleus was digitally extracted from six images of the innermost coma of this comet, obtained with the Hubble Space Telescope's Wide-Field Planetary Camera 2 in the planetary mode between October 23, 1995 and October 17, 1996. Two different anisotropic, power-type laws were used to filter out the contribution from the dust coma: …
Hubble Space Telescope Imaging of the BL Lacertae Object OJ 287
Yanny, Brian; Jannuzi, Buell T.; Impey, Chris
Hubble Space Telescope WFPC-2 I-band (F814W) images of the BL Lacertae object OJ 287 and the surrounding field are presented. We find evidence of associated extended nebulosity near OJ 287, as well as a small nebulosity to the west, which may be spatially coincident with the position of previously observed radio emission. The brightness of a host …
Angular sizes of the faint blue galaxies
Im, M.; Griffiths, R. E.; Roche, N. +1 more
We investigate the angular sizes, morphologies and B-I colours of the 21≮I≮24 galaxies imaged on 10 Wide Field Planetary Camera fields. The number of galaxies with bluer colours (B-I<2.0) and moderately large angular sizes exceeds non-evolving predictions by a factor of ~2, but is consistent with pure L* evolution (PLE) models. There is also an…
Faint ultraviolet objects in the core of M13: optical counterparts of the low-luminosity X-ray source?
Ferraro, Francesco R.; Paltrinieri, Barbara; Fusi Pecci, Flavio +2 more
The core of the Galactic globular cluster M13 (NGC 6205) has been observed with WFPC2 on the Hubble Space Telescope through visual, blue, and mid- and far-UV filters in a programme devoted to studying the UV population in a sample of Galactic globular clusters. In the UV colour-magnitude diagrams derived from the HST images we have discovered thre…
Compressive character of low frequency waves driven by newborn ions at comet Grigg-Skjellerup
Coates, A. J.; Belmont, G.; Neubauer, F. M. +2 more
The investigation by Giotto of the environment of comet P/Grigg-Skjellerup has provided a large set of observations on cometary low-frequency waves for a weakly active comet, after the observations at comets P/Giacobini-Zinner and P/Halley. A large amount of waves are observed at frequencies close to the local water group ion cyclotron frequencies…
Vertical Structure of Jupiter's Atmosphere at the Galileo Probe Entry Latitude
Beebe, R. F.; Chanover, N. J.; Kuehn, D. M.
The vertical structure of Jupiter's atmosphere is examined to better characterize the latitudinal region of the Galileo probe entry site: +5°-10° planetographic latitude. One-hundred Hubble Space Telescope images of Jupiter taken with the 893- and 953-nm filters on 13 and 17 February 1995, 5 October 1995, and 14 May 1996 are analyzed, and a two-cl…