Search Publications
Modulation of Galactic Cosmic Ray Protons and Electrons During an Unusual Solar Minimum
Fichtner, H.; Scherer, K.; Ferreira, S. E. S. +5 more
During the latest Ulysses out-of-ecliptic orbit the solar wind density, pressure, and magnetic field strength have been the lowest ever observed in the history of space exploration. Since cosmic ray particles respond to the heliospheric magnetic field in the expanding solar wind and its turbulence, the weak heliospheric magnetic field as well as t…
The Physical Properties and Effective Temperature Scale of O-Type Stars as a Function of Metallicity. III. More Results From the Magellanic Clouds
Massey, Philip; Bresolin, Fabio; Kudritzki, Rolf-Peter +4 more
In order to better determine the physical properties of hot, massive stars as a function of metallicity, we obtained very high signal-to-noise ratio optical spectra of 26 O and early B stars in the Magellanic Clouds. These allow accurate modeling even in cases where the He I λ4471 line has an equivalent width of only a few tens of m Å. The spectra…
CME Projection Effects Studied with STEREO/COR and SOHO/LASCO
Temmer, M.; Veronig, A. M.; Preiss, S.
Based on a set of 11 CME events we study the impact of projection effects by tracking CME leading edge features in the plane of sky (traditional CME tracking) from combined STEREO-SECCHI and SOHO-LASCO observations up to 20R⊙. By using CME observations from two vantage points and applying triangulation techniques, the source region loca…
Spatially Resolved Spectroscopy of Sub-AU-Sized Regions of T Tauri and Herbig Ae/Be Disks
Najita, J.; Eisner, J. A.; Graham, J. R. +1 more
We present spatially resolved near-IR spectroscopic observations of 15 young stars. Using a grism spectrometer behind the Keck interferometer, we obtained an angular resolution of a few milliarcseconds and a spectral resolution of 230, enabling probes of both gas and dust in the inner disks surrounding the target stars. We find that the angular si…
Storms in the tropics of Titan
Brown, M. E.; Schaller, E. L.; Roe, H. G. +1 more
Methane clouds, lakes and most fluvial features on Saturn's moon Titan have been observed in the moist high latitudes, while the tropics have been nearly devoid of convective clouds and have shown an abundance of wind-carved surface features like dunes. The presence of small-scale channels and dry riverbeds near the equator observed by the Huygens…
Pingos on Earth and Mars
Burr, Devon M.; Tanaka, Kenneth L.; Yoshikawa, Kenji
Pingos are massive ice-cored mounds that develop through pressurized groundwater flow mechanisms. Pingos and their collapsed forms are found in periglacial and paleoperiglacial terrains on Earth, and have been hypothesized for a wide variety of locations on Mars. This literature review of pingos on Earth and Mars first summarizes the morphology of…
Validation of the coronal mass ejection predictions at the Earth orbit estimated by ENLIL heliosphere cone model
Odstrcil, D.; Kuznetsova, M.; Hesse, M. +5 more
Modeling is an important tool in understanding physical processes in the space weather. Model performance studies evaluate the quality of model operation by comparing its output to a measurable parameter of interest. In this paper we studied the performance of the combination of the halo coronal mass ejection (CME) analytical cone model and ENLIL …
Mirror structures above and below the linear instability threshold: Cluster observations, fluid model and hybrid simulations
Budnik, E.; Dandouras, I.; Génot, V. +6 more
Using 5 years of Cluster data, we present a detailed statistical analysis of magnetic fluctuations associated with mirror structures in the magnetosheath. We especially focus on the shape of these fluctuations which, in addition to quasi-sinusoidal forms, also display deep holes and high peaks. The occurrence frequency and the most probable locati…
Titan's stratospheric C 2N 2, C 3H 4, and C 4H 2 abundances from Cassini/CIRS far-infrared spectra
Irwin, P. G. J.; Teanby, N. A.; Calcutt, S. B. +4 more
Far-IR (25-50 µm, 200-400 cm -1) nadir and limb spectra measured during Cassini's four year prime mission by the Composite InfraRed Spectrometer (CIRS) instrument have been used to determine the abundances of cyanogen (C 2N 2), methylacetylene (C 3H 4), and diacetylene (C 4H <…
Photometric mass and mass decomposition in early-type lens galaxies
Grillo, C.; Rosati, P.; Lombardi, M. +1 more
Context: The largest spectroscopically selected sample of strong gravitational lens systems presented and analyzed to date is that of the Sloan Lens ACS (SLACS) survey. For the 57 massive early-type lens galaxies in the sample, photometric and spectroscopic measurements are available from the Sloan Digital Sky Survey (SDSS).
Aims: By using the…