Search Publications
The Acceleration of Pickup Ions
Giacalone, J.; Jokipii, J. R.
The well-established association of pickup ions with anomalous cosmic rays shows that acceleration of pickup ions to energies above 1 GeV occurs. At present, diffusive shock acceleration of the pickup ions at the termination shock of the solar wind seems to be the best candidate for acceleration to the high energies of anomalous cosmic rays, accou…
Globular Cluster Luminosity Functions and the Hubble Constant from WFPC2 Imaging: The Dominant Group Elliptical NGC 5846
Forbes, Duncan A.; Brodie, Jean P.; Huchra, John
The Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2) has several advantages over ground-based observations for the study of globular cluster luminosity functions (GCLFs) and distance determination. Here we present WFPC2 data on the globular clusters associated with NGC 5846. This giant elliptical is the dominant galaxy in a small…
Kinematic Studies of Herbig-Haro Objects in the Orion Nebula
Hu, Xihai
Kinematic studies of most of the Herbig-Haro objects in M42 have been carried out. The proper motions of some of these objects have been determined through HST narrow band filter images taken four years apart; radial velocities of these objects have been obtained from high resolution échelle spectra taken at the Kitt Peak observatory using the Cou…
Ultraviolet Spectroscopy of the SL9 Impact Sites. I. The 175-230 nm Region
McGrath, Melissa A.; Yelle, Roger V.
We present a comprehensive analysis of spectra in the 175-230 nm wavelength region obtained by the Faint Object Spectrograph of the Hubble Space Telescope (HST) to determine the abundance of molecular species in the vicinity of the G and L impact sites. Data were obtained on July 18, roughly 3 hr after the G impact, on August 9, and on August 23. …
The central star of the planetary nebula NGC 6302.
Pottasch, S. R.; Beintema, D.; Vandenbussche, B. +3 more
Selected results from the ISO spectrum of NGC 6302 are reported. The intensity of the high ionization [Mg VIII] line is given. The controversy concerning the mechanism of ionization of the high ionization stages, and especially the [NeV] lines is discussed. It is concluded that all lines can be reproduced in a photoionization model, if the tempera…
Observations of Comet P/Faye 1991 XXI with the Planetary Camera of the Hubble Space Telescope
Lamy, P. L.; Keller, H. U.; Toth, I. +3 more
Comet P/Faye 1991 XXI (1991 n) was observed with the planetary camera (PC) of the Hubble Space Telescope (HST) between October 29 and November 21, 1991, when its geocentric distance was in the range 0.62-0.67 AU. The resulting high resolution-a single PC pixel projected to a distance of ∼20 km at the comet-made it possible to clearly discriminate …
IUE Observations of Four Known/Suspected Magnetic Cataclysmic Variables
Szkody, Paula; Silber, Andrew
We present lUE spectra of the known magnetics (RX J0515+0105, H1752+081 [V2301 Oph]) and the suspected magnetics (H0459+246 and H0857-242 [VZ Pyx]). The flux limit for H0459+246 is consistent with either a magnetic system or a very large value for the reddening. The AM Her system with the longest orbital period (RX 10515+0105) has a very high UV l…
Determination of interstellar pickup ion distributions in the solar wind with SOHO and Cluster
Möbius, E.; Lee, M. A.; Rucinski, D. +1 more
Over the last 10 years, the experimental basis for the study of the local interstellar medium has been substantially enhanced by the direct detection of interstellar pickup ions and of interstellar neutral helium within the heliosphere. Pickup ions can be studied for a wide range of interstellar species. However, currently the accuracy of the meth…
Absolute Reflectivity Spectra of Jupiter: 0.25--3.5 Micrometers
Baines, K. H.; Nicholson, P. D.; Simon, A. A. +6 more
The world-wide observing campaign of the Comet P/Shoemaker-Levy 9 (SL9) impacts into Jupiter during July 1994 has led to an unprecedented quantity of imaging data, predominantly in the visible to near-infrared wavelength regime. In an effort to provide reference brightness values for Jupiter at all latitudes, we present a compilation of absolute r…
Very cold dust associated with molecular gas.
Prusti, T.; Burgdorf, M.; Laureijs, R. J. +4 more
We report the detection of very cold dust in a small and isolated dust cloud. Observations at 60, 90, 135, and 200µm show a constant surface brightness ratio I_135_/I_200_ and a flattening of I_90_/I_200_ towards the cloud centre. The dust temperature derived from the far-infrared colours can be confined to the range of 12-15K assuming a λ^-…