Search Publications
The Three-Dimensional Extent of a High-Speed Solar Wind Stream
Balogh, A.; Goldstein, B. E.; Bame, S. J. +5 more
A primary goal of the Ulysses mission is to study the 3-dimensional structures making up the interplanetary medium, and example of which is the high speed solar wind stream observedin situ by Ulysses beginning in July 1992. In order to study the longitudinal extent of this stream as a function of Ulysses' increasing heliographic latitude, a second…
Simulations of Pickup-Ion Acceleration at Quasi-Perpendicular Shocks
Giacalone, J.; Jokipii, J. R.
We present results from hybrid simulations (kinetic ion/fluid electron) of the interaction of interstellar pickup ions with collisionless shocks. Since cross-field transport is unphysically suppressed in the one-dimensional geometry used here, an ad hoc scattering algorithm is used to model this effect. This is a necessary step to accelerate the p…
Entry of galactic electrons into the high latitude heliosphere
Simnett, G. M.; Tappin, S. J.; Roelof, E. C.
Evidence is presented for the first detection of galactic cosmic ray electrons in the general energy range 1 to 20 MeV by the HI-SCALE instrument on Ulysses as it passed over the solar poles. The electrons manifest themselves by a strong latitude dependence of the background counting rates in the HI-SCALE detectors, in excess of that predicted fro…
Some problems of the detection of the high energy gamma-radiation in space
Fradkin, M. I.; Ginzburg, V. L.; Kurnosova, L. V. +8 more
The flux of the diffuse gamma-radiation in the Galaxy was measured with the instruments on board of the satellites COS-B and Compton Gamma Ray Observatory (CGRO). It was shown that the spectrum of the diffuse gamma-rays N(E) in the energy range from very low energy (some tens keV) up to some GeV may be represented by the expression N(E) = AE^kdE, …
The IUE Spectrum of the "O VI Sequence" Planetary Nebula He 2-55
Feibelman, Walter A.
The first IUE observations of the "O VI Sequence" planetary nebula He 2-55 are reported. The ultraviolet spectrum is dominated by strong emission lines of O V, C IV, He II, and C III], plus a number of weaker ions for which emission line fluxes were measured. N V lambda 1240 and C IV lambda 1549 show P Cygni profiles. The stellar terminal wind vel…
Ulysses-Voyager Study of Energetic Particles Associated With the Intense Solar Activity of March/June 1991
Keppler, E.; Reuss, M. K.; McDonald, F. B.
The intense solar activity centered in March and June 1991 produced some of the largest interplanetary disturbances over the past several solar cycles. For these events the Ulysses EPAC energetic particle observations near 3 AU are compared with those of the Voyager 2 CRS experiment near 35 AU. At Voyager 2 there is a single long-lived event exten…
Winds and Accretion in delta Sagittae
Mason, Brian D.; McAlister, Harold A.; Eaton, Joel A. +1 more
The ten-year binary delta Sge (M2 Ib-II+B9.5 V) is a zeta Aur binary containing an abnormally cool component. Combining our analysis of the system as a visual binary with Batten's radial-velocity solution leads to the following properties: i = 40 deg, a = 51 mas = 8.83 A.U. = 1893 solar radius, hence d = 173 pc; MB = 2.9 solar mass and …
Circumstellar gas and dust in 68 Ophiuchi (A0 IVe).
Waters, L. B. F. M.; Grady, C. A.; The, P. S. +10 more
We present photometry and spectroscopy of the A0IVe star 68 Ophiuchi, for which Vidal-Madjar et al. (1993) suspected the presence of a circumstellar disc of material similar to that found around β Pic. The UV and optical continuum agrees well with a Kurucz model with parameters that are consistent with the spectral type. 68 Oph is detected at 12 a…
Spectropolarimetry of the dwarf nova IP Peg
Dhillon, V. S.; Rutten, R. G. M.
We present spectropolarimetric observations of the eclipsing dwarf nova IP Peg in quiescence. The data show linear polarizations with a mean value of 0.10+/-0.06 per cent. There are no significant differences between the continuum and line polarizations and no significant variations with wavelength or binary phase. We argue that the measured polar…
Multiwavelength observations of the bright QSO HS 0624+6907.
Clavel, J.; Reimers, D.; Heber, U. +9 more
We present non-simultaneous multi-wavelength observations of the bright radio-quiet QSO HS 0624+6907 (V=14.2, z=0.37) discovered by the Hamburg Survey (Groote et al. 1989). HS 0624+6907 has a particularly strong UV-soft X-ray bump which turns over already at the shortest IUE wavelengths, and it has a steep (Photon index {GAMMA}=-2.9) soft X-ray sp…