Search Publications

Study of Coronal Transients in UV Line Emission

Noci, Giancarlo; Martin, Renato; Maccari, Lisa

We investigate the expected emission from coronal transients in the following spectral lines observable with the Ultraviolet Coronagraph Spectrometer (UVCS) on board SOHO: Hi Lα 1216 Å, Ovi 1032-1037 Å, Nv 1239-1243 Å, Mgx 610-625 Å, Sixii 499-521 Å, and Fexii 1242 Å. We calculate line intensities and profiles for typical CME conditions, and we an…

Plasma wave characteristics of the jovian magnetopause boundary layer: Can wave-particle interactions cause the jovian aurora?

Krupp, N.; Balogh, A.; Tsurutani, B. T. +10 more

Alfvén waves in the solar corona and solar wind

Velli, M.; Pruneti, F.

Improvement of proper motions for Hipparcos stars with photographic plates.

Wang, Jia-Ji; Tang, Zheng-Hong; Wang, Shu-He +1 more

Using the PPM catalogue as a preliminary reference catalogue, the authors have reduced 17 exposures on 9 plates taken with the 40 cm refractor at Zo-Sè Station of Shanghai Astronomical Observatory in about 30 years. By means of the central overlapping technique and the iterative process, high-precision positions and proper motions of 28 PPM stars,…

Compton-Getting Factor and Latitude Variation of Cosmic Rays

Potgieter, M. S.; Heber, B.; Ferrando, P. +3 more

Is it possible to observe the emission from the boundary layers of FU Ori stars?

Rossi, C.; Giovannelli, F.; Vittone, A. A. +3 more

Our estimates show that the optical depth of the stellar wind from the FU Ori stars FU Ori, V1057 Cyg, and Z CMa in the Balmer and Paschen contunua can be greater than unity. It is probably for this reason that no optical and ultraviolet emission is observed from the innermost and hottest regions of these objects the boundary layers of accretion d…

Latitudinal and Radial Variation of >2 GeV Protons and Alpha Particles derived by Ulysses COSPIN/KET and Neutron Monitor Network Observations

Heber, B.; Raviart, A.; Dröge, W. +6 more

Investigation of the Guide Star Catalog

Smirnov, O. M.; Malkov, O. Y.

The Guide Star Catalog (GSC) was initially created at STScI to support the operational requirements of the Hubble Space Telescope (HST), specifically, to provide an all-sky set of reference coordinates for pointing and tracking. A new version of the catalog, GSC 1.1, includes bright stars from the HIPPARCOS INCA database. The GSC is widely used by…

Diamagnetic effect of the ion pile-up region of comet halley

Neubauer, F. M.; Israelevich, P. L.; Ershkovich, A. I.

The ion pile-up region in the comet Halley ionosphere observed on the inbound leg of the Giotto trajectory is accompanied by a decrease of the magnetic field strength. This magnetic field dip is explained by means of a diamagnetic effect of the plasma density increase in the pile-up region. No similar magnetic effect of the enhanced plasma density…

Extreme ultraviolet observations of the solar corona: first results from the coronal diagnostic spectrometer on SOHO

Mason, H. E.; Harrison, R. A.; Culhane, J. L. +9 more

We present first results from the Coronal Diagnostic Spectrometer (CDS) aboard the ESA/NASA Solar and Heliospheric Observatory (SOHO). CDS is a double spectrometer operating in the 151-785 A˚ range. This region of the solar spectrum is rich in emission lines from trace elements in the solar atmosphere, which can be used to derive diagnostic inform…