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Iron freeze-in temperatures measured by SOHO/CELIAS/CTOF
Livi, S.; Hsieh, K. C.; Wurz, P. +26 more
The CELIAS particle experiment on SOHO contains the Charge Time Of Flight (CTOF) mass spectrometer which measures the ionic and elemental composition of minor ions in the solar wind. In this paper we present iron freeze-in temperatures derived with a time resolution of 5 min. They indicate that some of the filamentary structures of the inner coron…
Calibration of the SERTS-95 Spectrograph from Iron Line Intensity Ratios
Brosius, Jeffrey W.; Thomas, Roger J.; Davila, Joseph M.
Goddard Space Flight Center's Solar EUV Rocket Telescope and Spectrograph was flown on 1995 May 15 (SERTS-95), carrying a multilayer-coated toroidal diffraction grating which enhanced the instrumental sensitivity within its second-order wave band (170-225 Å). Spectra and spectroheliograms of NOAA Active Region 7870 (N09/W22) were obtained in this …
Discovery of a Very Low Mass Binary with the Hubble Space TelescopeNear-Infrared Camera and Multiobject Spectrometer
Rebolo, R.; Zapatero Osorio, M. R.; Martín, E. L. +7 more
Hubble Space Telescope Near-Infrared Camera and Multiobject Spectrometer (NICMOS) observations of six brown dwarf candidates in the Pleiades open cluster are presented. One of them, namely CFHT-Pl-18, is clearly resolved as a binary with an angular separation of 0.33". The very low density of contaminating background stars in our images and the ph…
HST/FOC observations confirm the presence of a spectral feature in the optical spectrum of Geminga
Caraveo, P. A.; Bignami, G. F.; Mignani, R. P.
New optical and near-UV HST observations of Geminga are presented. When compared with previous ground-based and HST imaging, the data confirm and better define the presence of an emission feature centered at ~ 6,000 Angstroms and superimposed on the thermal continuum best fitting the extreme-UV/soft X-ray data. This feature may be interpreted in t…
Ultraviolet and Optical Spectroscopy Of AL Comae 1 Year After Superoutburst
Szkody, Paula; Howell, Steve B.; Sion, Edward M. +3 more
We present Hubble Space Telescope (HST) ultraviolet spectra of AL Com obtained with the Faint Object Spectrograph (FOS) during four epochs 10-14 months following its 1995 April superoutburst. During our 1996 observations, the continuum fluxes underwent a slow decline of 20%, while the spectrum showed Lyα and Si II absorption features indicative of…
Observational evidence for coronal mass injection by ``evaporation" of spicular plasma
Glassmeier, K. -H.; Wilhelm, K.; Schroeder, K. -P. +1 more
Despite being a common feature of the solar chromosphere, spicules are still a poorly understood phenomenon. Not much is known about their impact on the physics of the transition region and corona, for which spicules are believed to be the dominant mechanism for mass injection. We recently observed the spatial plasma structure of polar spicules in…
Extreme-Ultraviolet Sunspot Plumes Observed with SOHO
Kjeldseth-Moe, O.; Haugan, S. V. H.; Brekke, P. +4 more
Bright EUV sunspot plumes have been observed in five out of nine sunspot regions with the Coronal Diagnostic Spectrometer on the Solar and Heliospheric Observatory. In the other four regions, the brightest line emissions may appear inside the sunspot but are mainly concentrated in small regions outside the sunspot areas. These results are in contr…
Particle acceleration at corotating interaction regions in the three-dimensional heliosphere
Balogh, A.; Forsyth, R. J.; Desai, M. I. +3 more
We have investigated the relationship between the energetic (~1MeV) proton intensity (J) and the magnetic compression ratio (C) measured at the trailing edges of corotating interaction regions observed at Ulysses. In general, our results show that the proton intensity was well correlated with the compression ratio, provided that the seed intensity…
The Hubble Space Telescope Medium Deep Survey Cluster Sample: Methodology and Data
Nichol, R. C.; Griffiths, R. E.; Ostrander, E. J. +1 more
We present a new, objectively selected, sample of galaxy overdensities detected in the Hubble Space Telescope Medium Deep Survey (MDS). These clusters/groups were found using an automated procedure that involved searching for statistically significant galaxy overdensities. The contrast of the clusters against the field galaxy population is increas…
HST mid-ultraviolet spectroscopy of comet 46P/Wirtanen during its approach to perihelion in 1996-1997
Parker, Joel Wm.; Bertaux, Jean-Loup; Stern, S. Alan +6 more
We have used the Hubble Space Telescope Faint Object Spectrograph to observe the mid-UV spectrum of the ROSETTA mission target comet, 46P/Wirtanen, on three dates during the comet's apparition in 1996 and early 1997. During this time the comet moved inward from a heliocentric distance near 2.7 AU to 1.3 AU. The first measurement (22.7 July 1996) d…