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OI line emission in cool stars: calculations using partial redistribution
Jordan, C.; Koncewicz, R.
Radiative transfer calculations have been performed for five cool stars: α Tau, β Gem, Procyon, ɛ Eri and the Sun, for the purpose of investigating the behaviour of the OI emission over a wide range of stellar types, and its dependence on coherent photon scattering. These stars span a range of spectral types from F5 IV-V to K5 III and surface grav…
Constraining Electron Acceleration at a Standing Shock with HXR and Radio Observations
Mann, G.; Aurass, H.; Warmuth, A.
The acceleration of electrons to non-thermal energies in solar flares is one of the main unsolved questions in solar physics. One possibility for the production of these energetic electrons is acceleration at the reconnection outflow termination shock (TS). We use radio observations to constrain the characteristics of the TS, and hard X-ray and γ-…
Spatial damping of compressional MHD waves in prominences
Dwivedi, B. N.; Singh, K. A. P.; Hasan, S. S.
Aims:We study the spatial damping of linear compressional MHD waves in a homogeneous, isothermal, and unbounded prominence.
Methods: We derive a general dispersion relation invoking the Newtonian radiation and turbulent viscosity. The turbulent viscosity is derived from SUMER and CDS observations for Kraichnan and Kolmogorov turbulences. Since…
FUSE Observations of the Dwarf Novae UU Aql, BV Cen, and CH UMa in Quiescence
Szkody, Paula; Sion, Edward M.; Godon, Patrick +1 more
We report on FUSE spectra of three U Gem-type, long-period dwarf novae, UU Aql, BV Cen, and CH UMa, taken during their quiescence intervals. We discuss the line identifications in their spectra and attempt to characterize the source(s) of their FUV flux distribution. Archival IUE spectra of CH UMa and BV Cen in quiescence were identified as having…
A study of a macro-spicule and a transition region explosive event in a solar coronal hole
Doyle, J. G.; Xia, L. D.; Banerjee, D. +1 more
AimsSpicules and the higher macro-spicules (jet-like structures seen at the solar limb) are believed to be the dominant mechanism for mass ejection in the higher solar atmosphere outside active regions. But what is the connection between them and other small-scale structures in the Sun's atmosphere, like for example transition region explosive eve…
Solar Rossby Wave ``Hills'' Identified as Supergranules
Hathaway, D. H.; Cuntz, M.; Williams, P. E.
We explore the nature of ``hills'' observed on the solar surface that had previously been attributed to Rossby waves. We investigate the solar hills phenomenon by analyzing the output from a synthetic model based solely on the observed solar photospheric convection spectrum. We show that the characteristics of these hills can be explained by the c…
The ISOPHOT 170 µm Serendipity Survey. III. FIR statistics of optically identified galaxies
Lemke, D.; Klaas, U.; Stickel, M.
Aims: To shed more light on the integrated FIR properties of galaxies, the ≈2000 compact sources in the ISOPHOT Serendipity Survey associated with identified galaxies are investigated statistically. They provide the only sample large enough to determine the FIR properties such as dust temperatures and masses, FIR luminosities, and HI-to-dust ratio…
Venus upper atmosphere and plasma environment: Critical issues for future exploration
Luhmann, J. G.; Russell, C. T.; Cravens, T. E. +2 more
This chapter briefly summarizes our state of knowledge about the upper atmosphere and plasma environment of Venus. This is followed by a discussion of some of the outstanding remaining issues in the field beginning with the Venus Express epoch and continuing to Planet C and beyond. We compare with other planets, especially Mars, and emphasize open…
Photometry of Star Clusters in the M 31 Galaxy. Aperture Size Effects
Narbutis, D.; Vansevičius, V.; Kodaira, K. +2 more
A study of aperture size effects on star cluster photometry in crowded fields is presented. Tests were performed on a sample of 285 star cluster candidates in the South-West field of the M 31 galaxy disk, measured in the Local Group Galaxy Survey mosaic images (Massey et al. 2006). In the majority of cases the derived UBVRI photometry errors repre…
Huygens Probe descent dynamics inferred from Channel B signal level measurements
Plettemeier, D.; Bird, M. K.; Edenhofer, P. +3 more
The signal strength of the Huygens Probe Channel B transmission to the Cassini Orbiter was monitored during the Probe descent through Titan's atmosphere on 14 January 2005. A model of the Probe motion during the mission was constructed to include Probe spin, coning motion and tilt caused by varying wind speeds. This simple model is sufficient to r…