Search Publications
Ulysses observations of anti-sunward flow on Jovian polar cap field lines
Dougherty, M. K.; Balogh, A.; Forsyth, R. J. +4 more
We examine the energetic (∼MeV) ion data obtained by the Anisotropy Telescopes instrument of the Ulysses COSPIN package during two northern high-latitude excursions prior to closest approach to Jupiter, when the spacecraft left the region of trapped fluxes on closed magnetic field lines at lower latitudes and entered a region of open field lines w…
A Search for Proton Beams during Flares on AU Microscopii
Carpenter, K. G.; Robinson, R. D.; Maran, S. P. +1 more
We report the results of a coordinated observing campaign on the active M dwarf star AU Mic. The purpose of the campaign was to search for evidence of proton beams during the impulsive phase of stellar flares and to determine whether the energy contained in these beams represented a significant fraction of the energy budget of the flare. During a …
Far infrared properties of late type dwarfs. Infrared fluxes of K and M dwarfs.
Doyle, J. G.; Mathioudakis, M.
IRAS fluxes/upper limits are presented for a large sample of K and M dwarfs. Good agreement is found between the 12 micrometer fluxes and those derived from the photospheric models of Mould (1976). Relationships between the optical and infrared colors are derived. The active dMe/dKe stars appear systematically brighter in the infrared compared wit…
Forbidden Velocity Gas Detected in Ultraviolet Interstellar Absorption toward Four Distant Inner Galaxy Stars
Tripp, Todd M.; Sembach, Kenneth R.; Savage, Blair D.
We analyze International Ultraviolet Explorer high-dispersion observations of interstellar absorption toward HD 167402, HD 168941, HD 172140, and HD 173502, four distant, inner Galaxy, lower halo/thick disk stars (2°.3 < 1 < 5°.8, 6°.3 < |b| < 12°.3). On the basis of ultraviolet stellar photospheric and wind lines, we classify HD 16740…
Hard X-ray spectrum of 4U 1907+09.
Rao, A. R.; Chitnis, V. R.; Agrawal, P. C. +1 more
We have studied the binary X-ray source 4U 1907+09 in the energy range 20-100 keV, using a xenon-filled multilayer proportional counter telescope flown with balloons from Hyderabad in 1985 and 1991. Results of these observations are reported. The source was detected above 20 keV at a significance level of 13 sigma in 1985 and marginally detected i…
Solar wind thermal electrons from 1.15 to 5.34 AU: Ulysses observations
Balogh, A.; McComas, D. J.; Goldstein, B. E. +3 more
Using unique 3-d velocity space measurements by the Ulysses solar wind plasma experiment from 1.15 to 5.34 AU, we assess the radial gradient in thermal electron temperature. Until 3.8 AU, the gradient was steeper than previously reported but flatter than adiabatic; after 3.8 AU the gradient flattened. Trends in the observed electron distribution s…
MHD modeling applied to Giotto encounter with comet P/Grigg-Skjellerup
Neubauer, Fritz M.; Wegmann, R.; Schmidt, H. U.
First from a one-dimensional MHD model we derive estimates for position and shape of the bow shock applicable for arbitrary magnetosonic Mach numbers >1 in the solar wind. This generalization is important in the case of the Giotto encounter with P/Grigg-Skjellerup with the unusual interplanetary magnetic field (IMF) of 18 nT. We compare three-d…
Rotational modulation and flares on RS Canum Venaticorum and BY Draconis stars. XVII. UV spectroscopy and optical photometry of AU Microscopii in 1986.
Doyle, J. G.; Quin, D. A.; Butler, C. J. +2 more
We present IUE spectroscopy and optical photometry of the active late type star AU Mic. The UV spectroscopy allow us to measure the chromospheric and transition region line fluxes. No detectable variations attributable to rotational modulation were evident in either the chromospheric lines or optical bands. We have produced an emission measure cur…
Imaging the Bipolar Nebula around HM Sagittae
Paresce, Francesco; Hack, Warren J.
Hubble Space Telescope Faint Object Camera UV images are presented for HM Sge showing a bipolar optical nebula similar to that in R Aquarii and RX Puppis. The nebula extends to a distance of 0.174" with a P.A. of 135 degrees inside a faint halo extending to a radius of 0.28". A kinematic distance to HM Sge based on positions of features in the neb…
Water Production Rates in Comet P/Halley from IUE Observations of HI Lyman-β
Feldman, Paul D.; Combi, Michael R.
During the 1985-1986 apparition of Comet P/Halley, the International Ultraviolet Explorer (IUE) satellite observed the comet using both the long-wavelength and short-wavelength spectrographs. The combination of a spherical radiative transfer model and the hybrid gas-dynamic/Monte Carlo model for hydrogen coma, which had been used to analyze H Lyma…