Science Archives Publication System

A model for accelerated density enhancements emerging from coronal streamers in Large-Angle and Spectrometric Coronagraph observations

DOI: 10.1029/1999JA900505 Bibcode: 2000JGR...10510455S

Cargill, Peter J.; Schmidt, Joachim M.

Recent Large-Angle and Spectrometric Coronagraph (LASCO) white light observations, ranging between 2R_S and 32R_S, trace accelerated density enhancements in the vicinity of the Sun which can be detected as enhancement in the intensity of the Thomson scattered light. One interpretation of these observed density enhancements is t…

2000 • Journal of Geophysical Research

SOHO Ulysses 8

SWAN/SOHO H Cell Measurements: The First Year

DOI: 10.1016/S0273-1177(00)00012-0 Bibcode: 2000AdSpR..26..815Q

Bertaux, Jean-Loup; Lallement, Rosine; Quémerais, Eric +3 more

We present here an analysis of one year of data obtained by the SWAN instrument on board the SOHO spacecraft orbiting around the L1 Lagrange point at 1.5 × 10⁶ km sunward from Earth. This instrument is measuring the interplanetary Lyman ca background due to solar photons backscattered by hydrogen atoms in the interplanetary medium. The …

2000 • Advances in Space Research

SOHO 8

Interstellar Gas in the NGC 4410 Galaxy Group

DOI: 10.1086/309448 Bibcode: 2000ApJ...541..624S

Smith, Beverly J.

We present new radio continuum, 21 cm H I, and 2.6 mm CO data for the peculiar radio galaxy NGC 4410A and its companion NGC 4410B and compare with available optical and X-ray maps. Our radio continuum maps show an asymmetric double-lobed structure, with a high surface brightness lobe extending 3.6‧ (~100 kpc) to the southeast and a 6.2‧ (~180 kpc)…

2000 • The Astrophysical Journal

eHST 8

An analytical model to predict the particle flux on spacecraft in the solar system

DOI: 10.1016/S0032-0633(00)00052-0 Bibcode: 2000P&SS...48.1429J

Jehn, R.

In this paper an analytical meteoroid flux model is presented which extends from 1 to 10 AU and covers a mass range from 10 ^-18 to 1 g. The basic flux curve of the model by Grün et al. (1985, Icarus 62, 244-272.) is modified by an analytical multiplication factor in order to approximate the meteoroid flux as predicted by the five-popula…

2000 • Planetary and Space Science

Ulysses 8

A Synoptic View of the Subphotospheric Horizontal Velocity Flows in the Sun

DOI: 10.1086/308812 Bibcode: 2000ApJ...535..454G

Hill, F.; González Hernández, I.; Bogart, R. S. +3 more

Ring diagram analysis, a technique of local helioseismology, has been applied to 120 regions of 15^deg×15^deg over the solar surface in order to study the mass motions in the upper layers of the convection zone. The horizontal flows from ~0.95 R_solar up to the surface have been investigated in a region spanning 360

2000 • The Astrophysical Journal

SOHO 8

Possible emission lines from the gaseous beta Pictoris disk

DOI: 10.48550/arXiv.astro-ph/9908266 Bibcode: 2000A&A...356..691L

Feldman, P. D.; Lecavelier des Etangs, A.; Ferlet, R. +6 more

We present the results of exploratory HST observations to detect the emission lines of ions in the beta Pictoris disk with the spectrograph slit placed off the star. Possible emission lines from Fe II have been detected at ~10^-14erg cm^-2 s^-1 at 0.5'' from beta Pictoris, which would suggest a total Fe II density of …

2000 • Astronomy and Astrophysics

eHST 8

Simultaneous SOHO andYohkoh Observations of a Small Solar Active Region

DOI: 10.1086/309005 Bibcode: 2000ApJ...537..481G

Siegmund, O. H. W.; Fisher, G. H.; Acton, L. W. +2 more

We present new results from observations of a small active region taken with the SUMER spectrograph and Extreme Ultraviolet Imaging Telescope (EIT) on SOHO and with the Soft X-Ray Telescope (SXT) on Yohkoh. The SUMER study features line and continuum emission covering a wide range of temperatures and includes the density-sensitive O IV] λ1400 mult…

2000 • The Astrophysical Journal

SOHO 8

Simulations and Mitigation of Pile-Up in XMM CCD Instruments

DOI: 10.1023/A:1008179519098 Bibcode: 2000ExA....10..439L

Lumb, D. H.

Simulations of the XMM EPIC instruments are presented. They suggest the correct operating mode must be chosen to ensure that spectral analysis of the data is not compromised by `pile-up' effects. The performance is contrasted with the CHANDRA AXAF CCD Imaging Spectrometer, showing how the higher effective area but better over-sampling of its mirro…

2000 • Experimental Astronomy

XMM-Newton 8

Surface and Sub-surface Electrical Measurement of Titan with the PWA-HASI Experiment on Huygens

DOI: 10.1016/S0273-1177(00)00113-7 Bibcode: 2000AdSpR..26.1697H

Rodrigo, R.; López-Moreno, J. J.; Fulchignoni, M. +11 more

The Permittivity Waves and Altimetry (PWA) experiment is part of the Huygens Atmospheric Structure Instrument (HASI) presently `en route' toTitan as a part of the HUYGENS Probe carried by the Saturn orbiter CASSINI. When HUYGENS lands upon Titan, the Mutual Impedance (MI) probe, part of the PWA experiment will be set to a special mode to measure t…

2000 • Advances in Space Research

Huygens 8

Probing the magnetic topology of coronal mass ejections by means of Ulysses/HI-SCALE energetic particle observations

DOI: 10.1007/s00585-000-0129-4 Bibcode: 2000AnGeo..18..129M

Sarris, E. T.; Malandraki, O.; Trochoutsos, P.

In this work, solar flare energetic particle fluxes (Ee geq 42 keV) observed by the HI-SCALE instrument onboard Ulysses, a spacecraft that is probing the heliosphere in 3-D, are utilized as diagnostics of the large-scale structure and topology of the interplanetary magnetic field (IMF) embedded within two well-identified interplanetary coronal mas…

2000 • Annales Geophysicae

Ulysses 8